Palladium plating before Rhodium?

I have a question…Has anyone worked with rhodium plating
anti-tarnish sterling? Do you still have to nickel or palladium
plate the sterling before placing it in the rhodium bath so that it
does not contaminate the rhodium? Has anyone used palladium plate
between sterling and rhodium at all? Did this work as well or
better than nickel plate? Who supplies palladium for plating in the
US?

Thanks!
Krista