Can we choose what midi in goes to a track?

We can select what midi channel goes to a track, but if we have more than one midi in (e.g. Usb + din) then what? Can we choose which input is fed to the track?
I can not seem to find anything about this.

no, only channel

But then, since we have more than one midi in, what should we expect Hermod to do? Will it merge all incoming midi or…?

yes, it merges midi in.
except midi clock/transport - the input for this is explicitly set in clock settings.
(see manual for details)

apart from this - midi thru allows specific control of which input gets sent to which output.

midi output is of course per output type as well.