On the check in / check out side you can handle both sides of the US at the same time but I think you will need to stop back for the BVI since you will have additional crew with you. If you were dropping people off or traveling with the same crew then you could complete both steps at the same time. The BVI paperwork is very easy on the return trip since your guests will simply need to complete the small form and then have their passport numbers added to the boat's paperwork.