09-01-2016, 07:05 AM
You just answered yourself. The way to go is to use combinator.bin from hashcat-utils, pipe it to hashcat and apply the rules on there as amplifier, like this:
$ ./combinator.bin wordlist1 wordlist2 | ./hashcat whatever.hash -w 3 -r whatever.rule
$ ./combinator.bin wordlist1 wordlist2 | ./hashcat whatever.hash -w 3 -r whatever.rule