Hi I am trying to fit an extra toilet in an en suite whilst doing the bathroom as well! The problem I seem to have, is the soil pipe is internal and the existing loo just has a 90 deg bend into it, I am thinking of putting a 110mm pipe from the soil with a Tee to the first loo and then on to another loo with a 90 deg bend. Is this ok or will I have problems when the furthest loo is flushed going back up the the other one? If not ok does anyone have any ideas?