OK, I figured out a solution coming at this from a different angle.
Instead of using the Group Member table as my reference table for my List Collector variable, I used the User (sys_user) table. I then used a function in a Script Includes to build the Reference Qualifier that I need. So, the Script Includes look like this:
var GroupMembersCriteria = Class.create();
GroupMembersCriteria.prototype = {
initialize: function(){
},
allGroupMembers:function(){
//Only return active users who are members of selected Group
//get selected Group from SC Variable
var include = '';
var selectedGrp2 = current.variables.group;
//return all members of selected group
var users2 = new GlideRecord('sys_user_grmember');
users2.addQuery('group', selectedGrp2);
users2.query();
//write all members user sys_ids to string
while(users2.next()) {
include += (',' + users2.user);
}
//return criteria string
return 'sys_id IN' + include + '^active=true^user_nameISNOTEMPTY';
},
type: 'GroupMembersCriteria'
};
And then call that from the Reference Qualifier on the List Collector variable like this:
javascript:new GroupMembersCriteria().allGroupMembers()
