Combinator

[undeath]

It's not directly supported. For best performance in your case do it like this:

1. create combined.txt
hashcat -a1 word1.txt word2.txt --stdout -o combined.txt

2. pipe in hybrid combined + mask
hashcat -a6 combined.txt ?d?d?d?d --stdout | hashcat -a 0 -m 0 hash.txt