Combinator or Rules Assistance

Hashcat is a great utility.  With it, I am able to recover my buddy's will after he lost the password in a cellular phone (single point of) failure.  It saves retyping dozens of pages of information.

The current goal is to recover the password that is partially known.  It is a combination of three words in pseudo-1337 ( i/1, e/@ and o/0).  Can Hashcat be set to combinator with three or more dictionaries?  Failing that, can someone assist with or minimally point to a means to design a rules file?

T. I. A.