Thanks for sharing your feedback.
We can prevent the agent assignment from the ticket list view page with the help of an Observer rule.
Let us consider the following scenario in which the agents A and B who are part of a group C. But to prevent tickets from Support Group being assigned to them you can create an Observer rule as mentioned below:
Agent is updated from any to Agent A
Agent is updated from any to Agent B
Events are performed by:
On ticket with these properties:
Group is not "Group C" (you would need to mention the group in which the agent is present)
Assign to agent : None
This particular Rule would make sure that all tickets assigned to Agent A and B are only in the Group C. If the group is a different one, ex : support then the ticket would not be assigned to them.
A similar rule needs to be created for each group present in the helpdesk.
Also, we have identified this issue and we are currently working towards a permanent fix for the same.
Please feel free to write out to firstname.lastname@example.org for further assistance