You can have separate checks with 1 ADR but I believe you will still have the mandatory tip percentage on them. I have been with a group that has done that before although I paid with my TIW so I already had a different mandatory tip so while I am fairly certain about the tip I have not done that part before. Make sure you let your server know when you meet them you want separate checks (honestly it should be easier there than many places since the meals are all the same price).