Hanger for 2 piece dress

One suggestion is the picture. other is get 2 hangers with a bar with clips. Put the top on the first hanger. Hang the 2nd hanger on the bar of the first hanger and use clips of first hanger to secure the 2nd hanger. Hang the skirt from the clips on the 2nd hanger. If you need more length between the hangers, use "S" hooks.

If you want them together, you could rig two hangers together with wire, connecting the two hangers with the desired amount of space.