Agree with all of the above comments about REF not passing call signs not in US Trust, but there is another way to create a link.  If you use a traditional XRF reflector, i.e. based on Dxrfd written by Scott Lawson, KI4LKF, then from modules A-D on that reflector you can link both to an REF and XLX reflector.  The modules on both REF and XLX must be in the A-D range, but you can cross-link.  For example, XRF module B can link to REF module A and also XLX module C.

John