Cimaira, open UVMapper Classic, and then File-->Load  Model, and find the object file for the figure you want to paint in the geometries folder.  Once the object file is loaded, you will see that the UVs for the different surface areas overlap as the multiple maps are all in the same UV space.

Go to Edit-->Select-->by Material and select all the materials that are on one texture map. For Victoria 4 they made this easy, as each set of materials is preceded by a number. You can see in the attached image that I have selected all the materials on the head texture map (all materials have the 1- prefix).

With the materials selected, go to Edit-->Assign-->to Group. Type in a name for a new group such as FaceMap and Click okay.  Do this for all the material groups.

When you are finished, Save Model with a new name -- Don't overwrite your original object file!

You can now bring this object into zBrush, and the groups will be the Material groups you created.