Hm… Well, it really comes down to what the Ground Control is going to let you do. I don't know anything about that device, but as I mentioned already, you can bypass an H9 either with a MIDI CC message (whose value is above 64) or with a program change message. You'll have to look into what possibilities the Ground Control will give you. If you have trouble figuring this out, maybe if you post the same question the H9 Owners Thread on the gearpage, someone there who has a Ground Control may be able to tell you what's worked for them: http://www.thegearpage.net/board/showthread.php?t=1488233&page=32
