Grouping: same subcategory in separate groups

Dear community,

Is there anyone who knows how to group on Category +Subcategory, when one of the subcategories appears under several groups?

Note: I need to be able to use these groups in a slicer.

My table:

Groups I need to set up:

Group 1: Category 1 + subcategory a

Group 2: category 2 + subcategory c

Group 3: category 2 + subcategories b,c,d

Note: subcategory "c" appears under both group 2  and group 3.

I have tried using Group function, however, I could only have subcategory c under one of the groups, not both.

ould

Thanks a lot in advance!