It would seem adventures take significantly more time than turnaround spent in the tavern. As such, I have trouble imagining one's characters meeting except in the odd fluke-of-chance situation. If it did, however, I would have the character I more want to see go on the adventure show interest in it, and the other pass it up, or show only passing interest. In the end, it's up to the DM who to accept (in most cases), but if a character doesn't want to be in a given adventure, nobody's going to make him. Well, normally, anyway...
Also, this could be a great opportunity for unexpected character development. Your elf ranger wants to got fight pirates more than your dwarf fighter? Why? Is the dwarf afraid of water? Was the elf's dog killed by pirates? Is the dwarf afraid of being recognized by the enemy as their old captain, now retired?
