Best Source of the Hive Mind Ability for This?

[Rubik]

So, I've got a dvati society mind (http://dsp-d20-srd.wikidot.com/society-mind) that I've tricked out with some manifestations of Mind Seed (http://www.d20srd.org/srd/psionic/powers/mindSeed.htm) and permanent Fission (http://www.d20srd.org/srd/psionic/powers/fission.htm). Since it's level 20, it has telepathy without regard to distance or planar boundaries, and so I have the Mindsight feat. I managed some cheese with Fusion (http://www.d20srd.org/srd/psionic/powers/fusion.htm), Astral Seed (http://www.d20srd.org/srd/psionic/powers/astralSeed.htm), and some hagunemnons (http://www.d20srd.org/srd/epic/monsters/hagunemnon.htm), so I can choose up to four (non-deific) creatures to pull Ex abilities from at the same time. I've got 8 bodies available, so one of the abilities is going to be hive mind. What would be the best monster to pull this from to keep all of the bodies together as a unified whole, mind-wise, regardless of distance or planar boundaries?

Thanks for the help.

[Rubik]

So far the best one I've found has been the demonhive swarm in the MM4, but I was hoping for something with a bit more planar range.

Anybody have anything better?