New Post: Using New-SCSMIncident to add support group (nested) e.g. ABC\1LS

Have you tried getting the child support group first?  It would look something like this (note that example is for incidents):

$supportgroup = get-scsmchildenumeration -enumeration (get-scsmenumeration -name tierqueue | where {$_.name -eq 'dept1'}) | where {$_.displayname -eq '2LS'}

Then insert $supportgroup in place of "depts1\2LS" in your above example.

Or you should just be able to set the -supportgroup switch to "(get-scsmchildenumeration -enumeration (get-scsmenumeration -name tierqueue | where {$_.name -eq 'dept1'}) | where {$_.displayname -eq '2LS'})" (without quotes).

I haven't tried this, but hopefully that would work.