Two Guitars: Polymetric Time Signatures?

Hey all!

I have a two-guitar, polymetric composition I'm working on.
The top guitar plays a repeated riff in 5/4 time, for four bars.
The second guitar plays a repeated 5/8, 7/8, 5/8, 7/8 (also four bars) beneath them.

How can I format the two parts, so that the 5/4 remains on top, while changing the bottom part to the 5/8, 7/8 measures, allowing them to sound simultaneously?

Many thanks, and peace!
~ Justin