I agree with John. You could use a table saw but the angle would have to be 45* and the bottom might not be smooth anyway even then. A router bit will do a much better job. If you look in my uploads you'll seee a diagram of a grooving jig. If you rip strips the width you want the grooves to be on your TS that will take care of your spacing. Just add another spacer strip for each groove.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.