I have had some years with RV's but more importantly am an electrical engineer. You can just simply connect two shore connectors to the same location and put one on the front but you MUST use a switch to prevent having one of those be a live exposed connection DON'T do that...that can kill you. Safest would be to use a switch. A switch that handles 30 or 50 map, whichever you have, would be needed. You can get what's known as a mechanical transfer switch at a Lowes or Home Depot...I'm sure some form of one of those is what Airstream uses (although probably an automatic one). They aren't cheap though.
Bill & Jenny - 2014 Fleetwood Bounder 35K, 36 ft, Ford V10 - Blue Ox and SMARTCAR. Once/month traveler in Midwest and Southern US. Home - Nashville, Indiana (Beautiful Brown County)