I was out with my daughter toon lvl 9 Ftr, and a guildmate lvl 6 Rgr. I was on my lvl 15 Mage. Do I nerf thier exp if I am grouped with them. Thanks.

No you wont nerf the exp for them -- here is how grouping/exp works in dungeon runners:

While you are in a group, you will still get the same amount of exp. So if you are soloing and killing a mob, and you get 30 exp, when you come back with a group of 5 ppl and kill that mob, you still get 30 exp. However, the mob will be stronger since you are in a group, and therefore take longer to kill -- however the damage of 5 people will usually far outweigh the added difficulty of the mob, leaving you to kill faster, and in the end make more exp.

Now with that being said, there is a limit on the level range of characters when it comes to gaining exp - and that is that you will get exp as long as you are not more tha 5 levels higher than the group leader (maybe 4?) (Whoever is the group leader of the party sets the mob level in a dungeon, so lets say your level 9 is the leader -- in this case, mobs are level 9 - your levels 6 and 9 will get exp from all kills, however your level 15 will not get that exp - if your level 6 were leader, your levels 6 and 9 will still get exp, and again your level 15 will get none. Lastly, if your level 15 is leader, all 3 characters will be able to receive exp, but the downside is all mobs would be level 15ish and probably destroy your level 6 character, and maybe even the 9 lol)

You can tell if you will get exp from a kill by moving your mouse pointer over a mob, if it is gray named, that means it will give you no exp. Sorry if this is a little hard to read, just waking up lol, hope it makes sense though.

By the way, what is your character name in game -- I am NCSUSean -- if you ever have any questions feel free to message me there.

My Mage is Wyenn
Ftr is Rebarty
Ranger is Asulon

I didn't know we had a farter class! Oh yeah... gaseous blast and whatnot...

lawlz.
If that isn't a title it sure should be.
"Gaseous Fighter" perhaps.

Flatulent Fighter. Alliteration FTW!