I have done 3 without any issues.  I have not see 7 on it.... but I think it should be able to do it.  Only thing I might suggest is looking at CrazyGuys with the auto zombie fix.  With 7 it will be more important I would think.

Or write your own mod to do it.   But I'm going to say it should... but 3 is my max so I could be wrong.