We're still undecided as to whether we will have TA. We may just go directly with the hotel and through the airline to get group rates.
BTW, I called American Airlines the other day and got some information about their Group Wedding Program. The guests can get a discount if they book with your group, it doesn't matter where they leave from. They use a code you provide and get a cheaper rate. Great option for those who may not want to use a TA.