PF pit problems

[Winds of Nagual]

So, my summoner want's to specialize in pit/wall spells with an eidolon who has excellent bull rush skills. Say my summoner opens pit beneath some ghouls causing four to fall in (filling the four open squares). Then my enlarged eidolon successfully bull rushes an ogre into the pit. Do they all share squares? Do the ghouls take damage? Ghouls at the outside edge of the pit falling in share squares? What logistical issues should I work out with my GM before I start pulling this stunt?

Cheers!

[avr]

The ghouls and ogre will be using the squeezing rules. Involuntarily.

There are rules for falling objects (http://www.d20pfsrd.com/gamemastering/environment/environmental-rules#TOC-Table:-Damage-from-Falling-Objects) hitting people, but talk to your DM as house rules aren't unlikely for this stuff IME.