So far I've just picked a random world, brought a yak and overload lol. Last two camps were with 4 and 3 people in total which I got prayer, summoning and slayer xp from.
It seems like prayer xp is given to the first person who click the beam, and then summoning to the person who clicks on it first after it changes. But slayer is dependant on damage I think, as I didn't tank the last one, but did deadshot, then rapid fire and got the slay xp o.
12-Jun-2013 10:00:31