Limit the assignee to a specific group
Here’s a video on how you can limit the assignee to a specific group.
Use the following script as a workflow transition validator to allow transition only if the assignee is in a specific user group.
string errorMsg = "You can only assign issues to members of your same team";
if(userInGroup("Customer Relations Team", currentUser()) && userInGroup("Customer Relations Team", assignee)) {
return true;
}
else {
return false, "error", errorMsg;
}