Hello,
The best option would be to connect an aux switch to one of the stompboxes and set it to control Bypass in the AUX SW menu. Then in the MIDI XMT CC menu set that aux switch to transmit a MID I CC. On the other stompboxes set that same MIDI CC to control Bypass in the RCV CTL menu. This will give you a master Bypass from one switch.
Alan
