Firstly, I am most happy to see that recently kdenlive is able to handle a plurality of audio streams.
Maybe it is just here, in Europa, where we get larger numbers of parallel audio streams. In the earlier days, when kdenlive only handled the first one, from some broadcasters this is unfortunately the one for visually impaired. Then I used ffmpeg to map / copy the stream as desired onto the first audio stream.

Alas, with the recent addition of handling multiple streams, the situation is not much better; let's look at the following example:
Stream #0:1[0x20c](deu): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 192 kb/s (visual impaired) (descriptions)
Stream #0:2[0x20d](deu): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 192 kb/s
Stream #0:3[0x20e](deu): Audio: ac3 ([6][0][0][0] / 0x0006), 48000 Hz, stereo, fltp, 448 kb/s
is what i get with ffprobe.
With kdenlive I can now import all streams, but it doesn't give me (or I wouldn't know how?) the details of these three streams. They all display the same title: file name. Then I need to open a command prompt, fire up ffmpeg like above, and either disable those that I don't want, or ungroup, delete the ones I don't want, and regroup. Effectively, this doesn't make my daily editing life easier at all.
Maybe that's only me, but I'd rather SEE the descriptors directly in kdenlive, e.g. in the Project Bin (e.g. "(deu): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 192 kb/s") and drag and drop the required one to the timeline.
I would rather not handle the streams on the timeline itself, because usually here in this region I easily get 4 or more audio streams, and then I'd have to furnish 4 or more audio tracks, taking up real estate simply to remove 3 or 4 immediately that I don't want.

My excuses in case I overlooked an already existing solution to this, and thanks in advance!