A Bandpass box (assuming 4th order) has linearity issues, and takes a lot of space.
A properly designed ported box will make them shine, and you don't need to separate them, you can have them in one box, and have no issues.
Though one question, in case you didn't buy them, why 2 JL 500/1 instead of 1 JL 1000/1? It would be cheaper, you'd have less wiring, and not worry about equal power distribution.