Transfer tickets within own group only

Its a simple issue . I want a user with a ticket in group 1 to be able to transfer the ticket to people in group1 only .
I believe the default is allow transfers to anyone in any group …

How do you grant the “OwnTicket” right to users? Maybe you can use a ticket role to distribute that right and add the group in which the users who should be able to own a ticket to that role