You have to accelerate both pieces to the same speed, which implies (in a rotational launcher), the same G (acceleration). Maybe there's some configuration whe

You have to accelerate both pieces to the same speed, which implies (in a rotational launcher), the same G (acceleration). Maybe there's some configuration where the leading payload pushes air out of the way for the first few km (the 'real' payload drafting behind), but the blocking payload isn't given enough energy to reach orbit and falls short. Seems like the following payload would crash into the leading one though.