what sororities at a&m highly recommend rec letters?

I would contact your local Panhellenic and register. They will help you gather all of the recommendation letters needed before recruitment. I would for sure get a letter for each chapter to keep your options open.

It's a good idea to already begin making a list of sorority women you know who could write you a rec. Your local pan. can help you in cases where you don't know anyone.

All.of.them. You might also consider letters of support (or additional recs) to chapters that really interest you. True letters of recommendation (from people who know you) are better than the information only recs that some of the local Panhellenic groups will arrange for you.

In other words, start asking everyone you know if they are greek or they know someone who is. Teachers are often a good place to start.

You will need recs for all of them.