code: function removeDataEntityFromAllGroups(connections, dataField, dataValue, cb) {
    if (!contains(GROUP_MODEL_DATA_FIELDS, dataField)) {
      return cb(new Error('Invalid group field specified: ' + util.inspect(dataField)));
    } else if (!validString(dataValue)) {
      return cb(new Error('Invalid value specified for field: ' + util.inspect(dataValue)));
    }
  
    var conn = connections.mongooseConnection;
    var groupsModel = models.get(conn, models.MODELNAMES.GROUPS);
    var query = {};
    query[dataField] = dataValue;
    groupsModel.find(query).exec(function(err, groupsList) {
      if (err) {
        return cb(err);
      }
      var groupsToUpdate = groupsList || [];
      var groupsUpdated = [];
      async.each(groupsToUpdate, function(group, cb) {
        var where = group[dataField].indexOf(dataValue);
        if (where < 0) {
          return cb(new Error('value (already found) missing from groups field: ' + util.inspect(group[dataField])));
        }
        group[dataField].splice(where, 1);
        group.markModified(dataField);
        groupsUpdated.push({_id: group._id.toString(), name: group.name});
        group.save(cb);
      }, function(err) {
        if (err) {
          return cb(err);
        }
        return cb(null, groupsUpdated);
      });
    });
  }
docs: /*
  removeDataEntityFromAllGroups(connections, options, cb)
  
  connections: {
  mongooseConnection: ...
  }
  
  options: {
  uri:       db connection string,
  userEmail: user email address string
  }
  
  cb  - callback function (err, groupList)  groupList : groups removed from