Prevent Duplicate selection of select_one inside a double repeat

Hello All,

I am trying to prevent double selection of a select_one option within nested repeats. I am able to get it working for the first repeat based in examples from this forum, but when I create a nested repeat I cannot get the second 'prevent double selection' to work.
I am sure it is because I need to reference the first repeat within the calculations but I am not sure how to do this, currently I am using '..' but it seems to not be reading the path.
I appreciate any guidance on this issue. I have attached an example form.
NoDuplicatesDoupleRepeat.xlsx (21.3 KB)

Thanks