I have a question that doesn't seem to be answered by the text!
Say three adventurers confront a gang of goblins, six of 'em. They manage to neutralize the threat (let's say they kill four and the other two run away). That's 60 xp. Do you think each adventurer deserves the full 60 xp, or a mere 20, given that that's their "share"?
Since treasure is supposed to be awarded at a rate of 2-3 times the xp of relevant encounter-dangers, it seems like divvying the xp among the adventurers is the way to go, for both treasure and for beating monsters.
My dungeon-in-progress has five encounters off the Level 1 column, running about 360 xp. Combine that with 1000 gp in treasures to be found, and that would put a single character at or near level 2, or three characters would be a bit under halfway to 2nd. Given that it's a pretty short adventure, that seems reasonable.
OK, so maybe I answered my own question. Do you disagree?