I believe the 6% includes the buying and listing agent, both at 3%. You can ask your listing agent to reduce their fees to 2.5% or 2% and see if they're willing to negotiate, but I've read that if you drop the buyer's agent fee, sometimes they'll just opt to skip over your house to another with a higher fee (more money in their pocket!). In this day and age, with the Interwebs and all that, I wouldn't think that would happen as frequently (since buyers can look for houses themselves and just ask an agent to schedule the showing), but I suppose there could be people who just blindly trust their agent.
As for what happens if both agents are from the same agency, that was specified in our contract (it went down a bit; I think to 2.5% each perhaps?), so just ask what their policy is and push back if you don't agree with it. There was also a clause in our contract about charging $250 or the like if we cancelled our contract before I think 6 months. It's fairly standard, so we just left it in, but that's something you might also want to look for and/or question.
We've also looked into just listing ourselves, or getting a flat-rate agent, but then we'd have to either be available to show the house ourselves or make it clear in the listing that we'd only show at night and on weekends, and we weren't sure if that would hurt us somehow (we ended up being about 50/50 on showings during the weekday and weekends).
Good luck!