The KACE SMA has a new Machine Action variable named: KACE_CUSTOM_INVENTORY_*.
The KACE_CUSTOM_INVENTORY_* field can be used to check a custom inventory value. The * will be replaced with the Display Name of the custom inventory rule. Only allowed characters are [A-Z0-9.-]. Anything else will be replaced with an '_' character.
For these instructions, TeamViewer remote control is used as the example.
"C:\Program Files\TeamViewer\teamviewer.exe" -i KACE_CUSTOM_INVENTORY_TEAMVIEWERID
"%PROGRAMFILES%\TeamViewer\teamviewer.exe" -i KACE_CUSTOM_INVENTORY_TEAMVIEWERID
Once those are done, you can use your machine action to connect to a machine with their TeamViewer ID.
You can also click the little blue question mark next to the Machine Actions title on General settings. It more details on the custom inventory variable.