This online tool allows you to input the people in your group and will tell you how evenly the EXP distribution of the group is.
http://rantsandflames.com/xpcalc/
I made this tool a year or 2 ago but haven't had it hosted in awhile. I got the idea from a Java tool made by Wiseto, but made it more convenient by putting it online.
I hope you find it useful.