There is currently no way in the web UI to create a Dynamic Group based on a group custom property.
also, trying to do it thru the API returns the following:
Invoke-SwisVerb : Containers does not support adding dynamic member definitions for other container entities, only static definitions are allowed.
At line:5 char:1
+ Invoke-SwisVerb $swis "Orion.Container" "AddDefinitions" @(
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [Invoke-SwisVerb], FaultException`1
+ FullyQualifiedErrorId : SwisError,SwisPowerShell.InvokeSwisVerb
Please add a way to populate a group with other groups based on those groups custom properties.