Advanced reference qualifier script shows assignment groups based on who is assigned to

var assignedTo = current.assigned_to.toString(); // Important: Convert to string
    var userGroups = [];
    var grMember = new GlideRecord('sys_user_grmember');
    grMember.addQuery('user', assignedTo);
    grMember.query();
    while (grMember.next()) {
        userGroups.push(grMember.group.toString()); // Add group sys_ids to the array
    }
     if (userGroups.length === 0) {
      // The user is not in any group, so return an empty string to show no groups.
        return '';
    }
     // Build the query for the Assignment Group table.
    var query = 'sys_idIN' + userGroups.join(','); // Efficient "IN" query
     return query;