@Torsten I hate to admit this, but I'm going to need to see a picture of a sample set of such racks. You likely have some around here elsewhere.
I started, mistakenly, making racks in the background rack - those are all embedded and are thus un-recyclable. Back to the drawing board!
I added a new linked rack, but once inside I noticed the outputs available were only "Plugin", "Embedded Rack", Embedded Rack (from File)", and "Media Player". I clearly was in the wrong district.
So, I suspected you meant to add an input port directed simply to "Output Port - Rack MIDI Out". But there is no way to re-name the "Midi Out" items. I am seeing nowhere that I can specify a "Notes", "Controllers", etc. output. So, I'm stumped at the start.
Please, some explanation and clarification for this process in visuals?
P.S. - This came right at the heels of my creating several filtered input items in the "Options/MIDI Ports" section, which seemed a bit cumbersome, but universal. The state changes can still apply to the input sections of the songs, and they are each named. Having taken this road is probably why I am confused now by your explanation, using racks instead of the Options/MIDI Ports approach.
The example below abstracts a single pad that is set to toggle on the Alesis QX49 so it can send and hold a drone "one finger wonder" note on any of my drone-worthy synths, in this case each of the two Korg Wavestations. The note sent from the Alesis stays constant (isolated via filters in the "Options/MIDI Ports" section), which I transpose to the desired note from the "MIDI Route" settings in the rack. (Those update with state changes, whereas filter-based transpositions in the rack do not.)