the way your question is phrased, I think you're asking if your friends have to use your Realtor as their Realtor. And the answer to that question is "no". They can use any Realtor they choose, or they can opt to represent themselves.
But if I'm reading the subtext properly, I think you might be asking if you will have to pay commission for those buyers, if they should choose to buy the house ... 'because they're your friends'. And the answer is going to depend on what you've written into your exclusive marketing agreement.
Most likely, you will still owe commission, unless you specifically excluded those friends from commission, in your agreement. And if you had, you'd probably have remembered that.... more