You're going to have to look at the ingredients of the vitamins and supplements, since they're all different.
See if any of them have the same active components. For example, it would be pretty common for a multivitamin to also have some of the B vitamins in it.
Then add up the total amount of anything that overlaps. Google and see how much of it you can take without overdosing! A lot of things should be fine if you take 200 % or whatever, but just make sure.