Bike Rack on Big Country

We have sold our Crossroads Cruiser 5th wheel and are now on the verge of ordering either a new Big Country 3250TS or 3300RL and of course I have a question or two. We have two bikes and a bike rack that we have used on the bumper of our old trailer. I know Lipperts stand on attaching to their frames and voiding the warranty but I am trying to see if people have been towing with a bike rack and bikes mounted to the bumper of a Big Country. Does anyone know if we are ordering a trailer can something be added at the factory to support a rack and two bikes? Thanks