Ditto to what Bobby Bob said in his post.

I have heard that in Ireland the A part is called the "tune" and the B part is called the "turn." By its very nature the pub session, unless it is a small one, is not kind to the whistle. And playing the whistle in its high register can result in a very shrill and sometimes unpleasant sound. You stand the chance of being heard more but liked less.

I don't know if there is a sensible solution to this problem. Maybe start a smaller session somewhere else? Or get together with friends in someone's house. In the session setting you might be better off just knowing that you're adding to the mix. Wait a minute, there is a solution! Learn tunes no one else in the session knows.

Richard