There is an add on called Molecular.  http://pyroevil.com/molecular-script-download/.  It makes the particles act as rigid bodies.  The particles can be linked to each other as well.  

Here is a little teaser trailer the creator made: https://www.youtube.com/watch?v=_5QkPnPDcfc.  I hope this helps!

hard self collision: make particles occupy space
What is the correct adjective form of the word hire? I have seen references to both hireable and hirable. 

I checked using Google's Ngram viewer book search and it appears that both have been in use since the 1800s with hirable becoming a bit more popular in the past decade or so:


