Almost all the sims allow "customisation" at that level. E.g. in FMS you could either modify throws or even switch the aileron channel off. RF, Aerofly and CSM are similar. They're just the ones I know.

Of course you'll have to bear in mind that many 4-channel planes will be very difficult to fly without ailerons as they don't have enough dihedral for the rudder to be effective for anything other than pointing the nose in a different direction.

Steve