QuoteLATER EDIT: Just to make sure, how many categories do you need? I counted 7, but I am not sure. Include also A and B as categories.
for the example of year 2, I've counted 9 categories. There were some details not explained in my original post (because to overview the problem I thought there weren't necessary). Now I attach a spreadsheet (ods) with the details of year 2, and as an example of the kind of display I suggested.
Some comments to this spreadsheet: the 2D division (diversity) could be managed as another group, in the same way as OPT group. Also, as I said before, maybe in the display some subactivities (like the OPT group ones) could be joined in one timetable to avoid so many ones.
Finally, this number of categories (9) would be needed for the year 2, which is the first I'm considering (because I know it well), but I cannot assure there's no other group with greater needs. I should look at it carefully, but maybe, if the solution is to add categories, would be better to put a greater maximum number to be sure it's enough.