Yes, letters and recs are basically treated equally. I suggest you keep a file with names of women and their contact info as you find out who you know that is a member of those groups on UA's campus. Then, next year, you will have this part of the process completed. If your friend is from your same town, she will be a great resource for this info, obviously.
Wait, wait, wait...do you mean "letters of support" as in "letters from active collegians"? Some groups do not treat them the same as all.
I'm confused, I thought you needed recs even if you had a letter of support...it was my understanding that the rec was more the "official" thing that some groups require to pledge a woman. Then again if someone was going to write you a letter of support I don't know why they wouldn't write you a rec.
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It is all 33girl's fault. ~DrPhil