Channel-Specific Offset Using Custom Filters in Reference ID

Hello there,

Is there a way to apply an offset in the Reference ID using a custom filter, but independently for a single channel only?
For example, to approximately compensate for a slight hearing loss around 3.5 kHz in the left ear.

As far as I understand, this currently only works for both channels simultaneously.
A function like this could also be generally useful, I think.

Thank you very much!

Alexius