I think they should keep the amount of xp any given monster can give out at a set amount, like it is now, to keep the metagaming down. If they're worth more exp as a total when killed by a team than an individual, it's wasting exp to fight alone. In other words, if a team of 2 gets a combined total of 6 exp rather than 4, as suggested above, then forming such groups would give the players an unnatural advantage. It would probably only be really relevant at the beginning where the enemies are essentially just free experience points though.
I can understand fewer experience points for large groups of players just because there's no risk or challenge involved. Do 5 demigods all jumping one minotaur really deserve any kind of reward for such an effortless task?
I think the best solution is probably for the game to give the same amount of exp out for each monster, regardless of how many demigods were involved in the kill, and to divide that number as evenly as possible. In 3 demigods vs 1 minotaur, if the game can do fractions of experience points, then 1 1/3 points to each, and if not, then 1 experience point to 2 demigods, and 2 experience points to the third. They could have it go to the demigod who did the most damage, who got the killing blow, or just by picking one randomly. I don't think the method of selecting who is awarded the extra point would be a big deal, since the game is supposed to be about teamwork anyway.
