But if i can set the ISS channel and then a remote anemometer channel differently on the same console that could work fine.
No, what you're being told (definitively!) is that you can't do this on the same console - you'd need two consoles.
I'm not absolutely certain that NHWF5510 is receiving the same thing you're transmitting.
Is it not possible to have:
Console A with the ISS set to Channel 1, and it receives all data from the ISS including the ISS-attached anemometer:
Additional console B with the ISS set to Channel 1,
and the anemometer transmitter and console anemometer setting set to Channel 2, and it receives all non-anemometer data from the ISS, and anemometer data from the anemometer transmitter on channel 2.
In other words, 2 side-by-side consoles, showing
all the same data
except for different sources for wind.
I know that's additional expense - 2 consoles and perhaps 2 loggers - but ...........