Question about leveling with 3 mages

I have a few questions about leveling with 3 mages.
First off, how exactly do I make up the experience for being in a group with 2 others?
I was thinking that I guess it might make up for it because you have to kill 3x as many mobs for all the drops you need to complete the quest, but what about quests that require you to just simply kill a certain mob?
Over time that could put a big dent in your experience, atleast I would think.
Second is for quests that that drop something for everyone in the group, that would also kill experience, with 2.3 I guess that might be kinda different, but still.
I read the few stickies there were on leveling and class guides, but they weren't very specific on experience compensation.

It can get that way sometimes, you'll finish up in a zone and be a little underleveled for the next area but over time it evens out by being able to do elite and group quests that soloers don't do. With the addition of a few new quest areas (eg Mudsproket in Dustwallow) and the xp changes post 2.3 I don't think it will have a noticeable impact over all. As an anecdotal comparison, my 5-box team all dinged 70 at almost the extact spot in Kopp's leveling guide as my last 2 solo 70's did.

Alright thanks, I could probably also run through an instance a few times and that would compensate for it.
Thanks for the info again!