Build a collection of computers with slow network connections

This is going to be a little more difficult than simply creating a collection of PC that are reporting a connection less than 1gbps unfortunately...

I'm trying to find out how many computers in our 300+ PC network are testing out at or below 100 mbps. We have some strange network oddities happening (combination of janky misreporting switches, daisychained IP phones, etc) and I want to make sure that all of our users actually have a 1gbps connection to our network. While I've been able to easily build a collection that shows all of the hardwired PCs that are reporting a 100mbps connection, there are still going to be some PCs that are connected at 1gbps to their switch, but are slowed down by something else up the chain.

I have iPerf servers running on servers in each of our buildings so I am able to get relatively accurate readings if I run the tests one by one to the proper local server. 
I've been able to concoct an automated iPerf test through PDQ Deploy to run useful speed tests with useful data, but I'm not quite sure how to collect this information in Inventory. 

An example of the command I am running is as follow, but the IP can be changed to the pertinent server:

C:\temp\speedtest\iperf3.exe -c 192.168.200.18 -P 5

The results are listed as follows:

Connecting to host 192.168.200.18, port 5201
[  4] local 192.168.202.97 port 60205 connected to 192.168.200.18 port 5201
[  6] local 192.168.202.97 port 60206 connected to 192.168.200.18 port 5201
[  8] local 192.168.202.97 port 60207 connected to 192.168.200.18 port 5201
[ 10] local 192.168.202.97 port 60208 connected to 192.168.200.18 port 5201
[ 12] local 192.168.202.97 port 60209 connected to 192.168.200.18 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  14.1 MBytes   118 Mbits/sec                  
[  6]   0.00-1.00   sec  19.9 MBytes   167 Mbits/sec                  
[  8]   0.00-1.00   sec  16.4 MBytes   137 Mbits/sec                  
[ 10]   0.00-1.00   sec  15.9 MBytes   133 Mbits/sec                  
[ 12]   0.00-1.00   sec  21.2 MBytes   178 Mbits/sec                  
[SUM]   0.00-1.00   sec  87.5 MBytes   734 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   1.00-2.00   sec  22.8 MBytes   191 Mbits/sec                  
[  6]   1.00-2.00   sec  21.4 MBytes   179 Mbits/sec                  
[  8]   1.00-2.00   sec  15.1 MBytes   127 Mbits/sec                  
[ 10]   1.00-2.00   sec  14.1 MBytes   118 Mbits/sec                  
[ 12]   1.00-2.00   sec  16.9 MBytes   142 Mbits/sec                  
[SUM]   1.00-2.00   sec  90.2 MBytes   757 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   2.00-3.00   sec  22.2 MBytes   186 Mbits/sec                  
[  6]   2.00-3.00   sec  22.0 MBytes   184 Mbits/sec                  
[  8]   2.00-3.00   sec  18.5 MBytes   155 Mbits/sec                  
[ 10]   2.00-3.00   sec  12.1 MBytes   102 Mbits/sec                  
[ 12]   2.00-3.00   sec  17.1 MBytes   143 Mbits/sec                  
[SUM]   2.00-3.00   sec  92.0 MBytes   771 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   3.00-4.00   sec  17.5 MBytes   147 Mbits/sec                  
[  6]   3.00-4.00   sec  18.6 MBytes   156 Mbits/sec                  
[  8]   3.00-4.00   sec  13.8 MBytes   115 Mbits/sec                  
[ 10]   3.00-4.00   sec  19.5 MBytes   164 Mbits/sec                  
[ 12]   3.00-4.00   sec  18.9 MBytes   158 Mbits/sec                  
[SUM]   3.00-4.00   sec  88.2 MBytes   741 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   4.00-5.00   sec  18.5 MBytes   155 Mbits/sec                  
[  6]   4.00-5.00   sec  18.9 MBytes   158 Mbits/sec                  
[  8]   4.00-5.00   sec  15.2 MBytes   128 Mbits/sec                  
[ 10]   4.00-5.00   sec  23.1 MBytes   194 Mbits/sec                  
[ 12]   4.00-5.00   sec  15.5 MBytes   130 Mbits/sec                  
[SUM]   4.00-5.00   sec  91.2 MBytes   765 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   5.00-6.00   sec  15.0 MBytes   126 Mbits/sec                  
[  6]   5.00-6.00   sec  17.6 MBytes   148 Mbits/sec                  
[  8]   5.00-6.00   sec  16.0 MBytes   134 Mbits/sec                  
[ 10]   5.00-6.00   sec  21.1 MBytes   177 Mbits/sec                  
[ 12]   5.00-6.00   sec  17.8 MBytes   149 Mbits/sec                  
[SUM]   5.00-6.00   sec  87.5 MBytes   734 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   6.00-7.00   sec  20.2 MBytes   170 Mbits/sec                  
[  6]   6.00-7.00   sec  23.2 MBytes   195 Mbits/sec                  
[  8]   6.00-7.00   sec  16.0 MBytes   134 Mbits/sec                  
[ 10]   6.00-7.00   sec  19.0 MBytes   159 Mbits/sec                  
[ 12]   6.00-7.00   sec  16.9 MBytes   142 Mbits/sec                  
[SUM]   6.00-7.00   sec  95.4 MBytes   800 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   7.00-8.00   sec  20.5 MBytes   172 Mbits/sec                  
[  6]   7.00-8.00   sec  15.9 MBytes   133 Mbits/sec                  
[  8]   7.00-8.00   sec  21.4 MBytes   179 Mbits/sec                  
[ 10]   7.00-8.00   sec  15.9 MBytes   133 Mbits/sec                  
[ 12]   7.00-8.00   sec  16.2 MBytes   136 Mbits/sec                  
[SUM]   7.00-8.00   sec  89.9 MBytes   753 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   8.00-9.00   sec  19.1 MBytes   161 Mbits/sec                  
[  6]   8.00-9.00   sec  16.9 MBytes   142 Mbits/sec                  
[  8]   8.00-9.00   sec  21.4 MBytes   180 Mbits/sec                  
[ 10]   8.00-9.00   sec  17.1 MBytes   144 Mbits/sec                  
[ 12]   8.00-9.00   sec  17.5 MBytes   147 Mbits/sec                  
[SUM]   8.00-9.00   sec  92.0 MBytes   774 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   9.00-10.00  sec  15.8 MBytes   132 Mbits/sec                  
[  6]   9.00-10.00  sec  16.6 MBytes   140 Mbits/sec                  
[  8]   9.00-10.00  sec  18.4 MBytes   154 Mbits/sec                  
[ 10]   9.00-10.00  sec  19.2 MBytes   162 Mbits/sec                  
[ 12]   9.00-10.00  sec  19.9 MBytes   167 Mbits/sec                  
[SUM]   9.00-10.00  sec  89.9 MBytes   754 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec   186 MBytes   156 Mbits/sec                  sender
[  4]   0.00-10.00  sec   186 MBytes   156 Mbits/sec                  receiver
[  6]   0.00-10.00  sec   191 MBytes   160 Mbits/sec                  sender
[  6]   0.00-10.00  sec   191 MBytes   160 Mbits/sec                  receiver
[  8]   0.00-10.00  sec   172 MBytes   144 Mbits/sec                  sender
[  8]   0.00-10.00  sec   172 MBytes   144 Mbits/sec                  receiver
[ 10]   0.00-10.00  sec   177 MBytes   149 Mbits/sec                  sender
[ 10]   0.00-10.00  sec   177 MBytes   148 Mbits/sec                  receiver
[ 12]   0.00-10.00  sec   178 MBytes   149 Mbits/sec                  sender
[ 12]   0.00-10.00  sec   178 MBytes   149 Mbits/sec                  receiver
[SUM]   0.00-10.00  sec   904 MBytes   758 Mbits/sec                  sender
[SUM]   0.00-10.00  sec   903 MBytes   758 Mbits/sec                  receiver

iperf Done.

What I'd like to do is collect the final number (the one italicized and not in bold above) and and create a collection for every computer will results less than 100 (or any arbitrary number for that matter) to assist with troubleshooting.

Any ideas??

Thanks in advance!