You could try to sail both and hope that you don't get seperated at night or in fog, or in a storm. And then hope that if you do you will be able to get the ships close enough to transfer men and cargo. If a hostile ship appears and you try to do so you will most likely be caught as it does take considerable time for sailing vessels to come together and men to transer without risking damage.
Conventional wisdom would be to let the survivors who didn't join your crew try to make their way, or to kill them and scuttle the ship. Don't let me bully you though, players being unconventional often makes for a fun game.