Kees-
Modern rigs, use diode switching to engage filters. I suggest using just 1 relay for positive switching and the output of each filter be run through diodes to a commonality. It would reduce current flow to the relays by 50%.. My thought is simple- steering up front, but where the output goes is always the same..
Years ago, I did some modifications on solid state switching VHF amplifier for VHF Engineering in Binghamton, NY.. We could drive 40 watts at 146Mhz though 4 1N914's in parallel, 25 watts through 2 of them. Experimenting required --but 2-4 1N914's are cheaper than a relay. Smaller foot print too..
