Currently, my downstairs floor is done in ceramic tile. I am planning on installing (DIY) an engineered floor over the concrete, which will meet up with a bathroom door. I would like to keep the tile in the bathroom (to avoid the hassles of dealing with fitting the wood around the fixtures, etc). As the tiles are diagonally laid, there is no way to match up the wood and tile. Is there a good way to cut ceramic tile that is already glued down to the floor? I assume that as a worse case, I can pry out a the offending tiles in the bath room, and replace them with cut tiles (from some of the tiles that I am removing), but that sounds like a lot of work. Any suggestions would be appreciated.

I use a diamond bit blade in my gringer to cut ceramic. Havent done it when already on floor but do not see why it would not work.

It's going to be easier if you can use a transition piece like a t-mold to cover the cut edge. Use a glass cutter and straight edge to score the cut first then grind just this side of that scored line. Use a hand grout saw to cut out the grout up to the score line so it will not transfer "shock" to the tiles you are keeping. I've seen situations where grout is the only thing keeping the tile down.