To allow a user to create alias-servers only, and NOT sub-servers...from respective users Virtualmin/Webmin panels.
From admin/root it's not a problem...just de-activate Maximum allowed servers...set at 0...they can't create them, you can.
But what about the client side?
In my mind the choice in the templates should specifically be:
Maximum allowed virtual sub-servers.....choices
Maximum allowed virtual alias-servers...choices
If sub-servers is set to 0, the client only has the option of creating the allocated number of alias servers..which is the objective.
Surely I'm missing something here....kindly advise.