BruteForce with specific patterns

[Tito]

Hello all.

I have a list of hashes around ~14 char long.
I would like to understand if there is any way to brute force only with valid words.
let's say i have around 20k words that i believe that most of the passwords are "built" from.
i am asking if there is any way to brute-force the following way :
(?w - is a word from the 20k list,?s is a symbol)

?w?s?w?s?w?s

until now i just used combinator for 4 times but i got a file size ~30GB


Thanks in advance 

[undeath]

you can use princeprocessor

[atom]

Use -a 1 with the left wordlist having ?w?s?w?s and the right wordlist having ?w?s will give you full GPU acceleration