mkvmergegui - Help assigning specific subs to different audio choices?

[djmasturbeat]

Would someone be so kind as to tell me how, in mkvmerge I can assign specific subtitle choices to specific audio when that audio is selected?

for example (for a dual audio anime):
*assign signs-only subs with the English dub 2.0 and English dub 5.1 tracks,
* assign full English subs with Japanese audio.

I still would like these to be able to be turned off (not forced) from the player if so desired. thanks for any help.

apologies if the answer to this is located somewhere already, I really have looked.

EDIT:
I have been told this is not in matroska spec.

[sneaker_ger]

You cannot assign subtitle tracks to audio tracks in mkv.