so i think natively, you're not going to get this.
on the Assigned To field, you can configure the dictionary and select the "dependent" field of "assignment group" (whatever your assignment group field is)
then when you set your assignment group, you'll get only the group members.
however, i dont believe this works the other way around.
You'd have to write a filter that gets the assigned to, and then looks at the available groups. but if the assigned to is blank, then returns all groups.
edit the dictionary of the Assignment Group:
Change the "Use Reference Qualifier" to "Advanced"
set the Reference Qual to:
javascript : new getUserGroups().getGroups(current.assigned_to)
Then create a script includes:
Name: "getUserGroups"
Script:
var getUserGroups = Class.create();
getUserGroups.prototype = {
initialize: function() {},
getGroups: function(user) {
if (user) {
var groups = [],
grGroupMember = new GlideRecord("sys_user_grmember");
grGroupMember.addQuery('user', user);
grGroupMember.query();
while (grGroupMember.next()) {
groups.push(grGroupMember.group.sys_id.toString());
}
return "sys_idIN" + groups;
} else {
return "active=true";
}
},
type: 'getUserGroups'
};
Where the "active=true" is where you'll want your default filter for the assignment group if the assigned to is blank.
