My gaming group (and some NPCs) are shipwrecked on a desert island. I'd like the characters cooperate to survive in this hostile environment, because I want to make the game world really dangerous (so they _have_ to cooperate or die).

But two players ("lone wolves") have broken away from the group and entered the jungle alone.

Now, I have always encouraged the betrayal and division among the players, but not so soon. If I offer to these "lone wolves" challenges appropriate to their abilities, they hardly feel the need for a group. But if I do otherwise, they will likely die at 1st level.

Furthermore, I will have to tell two stories in the same session.

Does anyone have any suggestions? I have to force the meeting of the two groups or leave the "lone wolves" to die in the jungle.

(BTW, the game is Pathfinder, but I don't think it matters for the question. And please sorry my bad English.)