bad... bad... liked roni advises. I use to flush while pooping, usually helps.
I use to wait for an empty restroom - not always possible.
I use to try handcap restrooms in emergency cases. Good option. If anyone asks why are you using it, just ask "Do you have some spare time?".
At last, but not the least. Think that YOU are the attacking party, not the offended one! You have the noises, the smell, the urgency and the POWER!! Flee!!! This restroom is MINE!!!! uahahahahah!
Usually, one good thing about getting older is that you really don't mind anymore.
Have fun, if you find it possible!!!!