I am in AA and probably 50% of the people in my meetings did both Alcohol and others drugs. Many of the folks whose DOC wasn't alcohol simply like AA better. Some identify themselves as and "alcoholic" and some as an "alcoholic addict."
While our group keeps it mainly to alcohol some that drank and drugged or just drugged say "when I was out there" or "when I used"....The bottom line is we are united with a common cause which is to help each other live a sober life. I think you might want to hit some AA meetings if you don't find luck in NA. I have not been to NA but many seem to like it. I do find a lot of folks coming to AA from there though. Maybe it's just because there are more meeting options??
Good Luck!