It might be as easy as having the drones land as-is, let the lead plane taxi to the hotpad, rearm, and taxi BACK to the end of the runway with the drones. You pull up so that you're touching the drones, throttle back for 20 seconds (kind of like hotpad) and then a message says "Drones are ready for takeoff" and when you roll down the runway they follow as if taking off for the first time.