Man, I wish this were a thing. I've been looking for something like this for ages to no avail. As far as I'm aware (and someone please, please, PLEASE correct me if I'm wrong!!), there isn't because the tagging system weights all the tags evenly.

It would be super cool if they had something for main vs. secondary pairing, but then, I guess beggars can't be choosers?

Le sigh.