Thx for all your replies !!
This topic with the associated tracks seems to be on desire since several years now - however I do not have any clue how complicated it might be to develop ... - I read all the old threads for that (thx to ma_t14), and for me some thoughts about the discussed functionality are a little bit "over-perfect".
I think, two simple checkmarks in the tagging zone will cover most of the requirements:
1. following track (= title number +1 of the same album) will be played always in sequence (Y/N)
2. previous track (= title number -1 of the same album) will be played always in sequence (Y/N)
If 1 = YES and 2 = NO, then track A and B are linked together, only when shuffle mode is choosing track A
If 2 = YES, and 1 = NO, then track A and B are linked together, only when shuffle mode is choosing track B
If 1+2 = YES, then track A und B are linked together, regardless if the shuffle mode is choosing A or B
If 1+2 = NO (= default), then is it like today - nothing changes