Hi @Aaron Duncan 
I just modified your script and it worked. PFB.

var myTeamsRequests = Class.create();
myTeamsRequests.prototype = {

    initialize: function() {},

    getRecordsCreatedByGroupMembers: function() {

        var userID = gs.getUserID();
        var groupArray = [];
        var user = new GlideRecord('sys_user');
        if (user.get(userID)) {
            var grMember = new GlideRecord('sys_user_grmember');
            grMember.addQuery('user', userID);
            grMember.query();
            while (grMember.next()) {
                var group = grMember.getValue('group');
                groupArray.push(group);
            }
        }

        var userArray = [];
        for (var i = 0; i < groupArray.length; i++) {
            var grMember1 = new GlideRecord('sys_user_grmember');
            grMember1.addQuery('group', groupArray[i]);
            grMember1.query();
            while (grMember1.next()) {
                var userId = grMember1.getValue('user');
                if (!userArray.includes(userId)) {
                    userArray.push(userId);
                }
            }
        }

        return userArray;

    },
    type: 'myTeamsRequests'
};

Dynamic filter:

Hope this helps.
Regards,
Siva