SPUtility.RunWithElevatedPrivileges Fails with getting SPUser from groups

Using SPUtility.RunWithElevatedPrivileges fails when trying to get SPUser objects from groups. It worked when I removed the privilege block, but this was not practical for non-admin users. The code below worked perfectly for me:

            Guid groupWebID = SPContext.Current.Web.ID;

            Guid groupSiteID = SPContext.Current.Site.ID;

            SPUserToken sysToken = SPContext.Current.Site.SystemAccount.UserToken;

 

            using (SPSite groupSite = new SPSite(groupSiteID, sysToken))

            {

                using (SPWeb groupWeb = groupSite.OpenWeb(groupWebID))

                {

 

                    SPGroup group = groupWeb.Groups["My Group"];

                    foreach (SPUser user in group.Users)

                    {

                        AllUsers.Items.Add(user.Email);

                    }

 

                }

            }