BG + RES with FH and LMB are a common stocking method. RES can cross with GSF and BG - not sure about with HBG but my guess is yes it is possible but is not something I would worry about. Unlikely to cause a problem. If you mix in BG with HBG over time the BG will prevail. You will need more forage than just HBG and RES to go with LMB assuming normal #s.