There is a difference between conforming and dynamic clothing. Only dymanic clothing is designed for the cloth room.

That said, there are several ways to use conforming items in the cloth room, although the results are spotty.

You can export the conforming item out as a OBJ and then import it as a prop. This requires that you know a little something about how to create a constrained group so the item does not fall apart when you run the simulation.

You can also do as you are doing. Simply add another simulation for each body part you are tweaking. They will be cumulative.

Again, the results are variable, but I have made it work on many occasions.