Welcome to the forums, ignore the grouchy regulars.

3 Mages are gonna be tough to multibox in 3v3s, you have lots of DPS, but no defense other than Ice Block, and no heals. I'm basing this off my experience with a priest and 3 Mages in 5v5s. It isn't pretty. Fear and Stealth are both your enemies, but AE vs 3 rogues does work well with a Priest, PoM + CoH + PoH FTW.

I really like Priest as a healer tho, but you could probably get any of them to meet your needs.