How to Automate Creation of Subnetworks

[EC1]

I have a Water Utility Network Model up and running, with various source/pressure subnetworks.
My Network includes the following relevant features: Water pipes and isolation valves 

I wish to create shut-off blocks using the isolation valves. By shut-off block I mean an area of pipe that can be turned off using the nearby isolation valves. I wish to set these up as their own individual 'isolation' subnetworks. 

Below is an example of what I wish to achieve, with the highlighted line being a isolation subnetwork. The red circle is a isolation valve, the red arrow is also a isolation valve. Note that the sub isolation valves (red arrow) are included in the isolation subnetwork. 

So far to define any subnetworks I have used the modify subnetwork tool through ArcPro. Manually setting isolation subnetworks will not be possible.

Is there a way to automate this process? 
Either through ArcPro, or through something like FME - is it possible to define these isolation subnetworks purely via changing attribute fields on the pipes/isolation valves or is there more back end things going on?

Thanks for reading. 

[G_Dillenger]

If you are able to select the valves you want, you can export them to a spreadsheet/table with the GUIDs. Then you could use those GUIDs in the spreadsheet created by the Export Subnetwork Controller tool to import a single batch with the Import Subnetwork Controller tool.

[EC1]

Thats useful, but how would I enter multiple the GIDs of the multiple isolation valves that create a shut-off block? It looks like in the exported subnetwork controllers csv theres only one FEATUREGLOBALID per subnetwork.

Or would I have to set up multiple SUBNETWORKCONTROLLERNAMES for each of the isolation valves that define all the isolation valves that go into a shut-off block? and those would all share the same SUBNETWORKNAME? If I was to do this on a large scale I could automate the naming process.