Controlling format of multicam clip?

I've got 2 HD Pal interlaced cameras (25i) and 2 X 4K (24p cine) cameras.

When I highlight the four cameras to make a multicam clip my choices are only HD at 25i. I can't get FCPX to create a 4K multicam clip (with the HD clips embedded).

I can make an HD 25i multicam, and later bring it into a 4K timeline ... that works.

But is there a way I can go straight to a 4K multicam clip? Given the above situation.

All ears,

Ben