Is it possible to hide sources on media player card?

I have a receiver in my GUI with about twice as many sources as there actually is (Marantz reports unused favourites as sources through the TCPIP system). Is there any way to hide unused sources on that card, maybe with the configuration file?

Hide them in the receiver itself

No, sorry. Tried that. It doesn’t work. At least not on my Marantz SR6008.

Edit: I know that because I have hidden all unused sources in the receiver. But it does show the custom names of the renamed sources, it just doesn’t obey hidden sources.