Linking users with each other from the site´s admin: User reference and beyond?

Hi there!
I´ve got a question that still goes unanswered since a long time, so after searching, and trying different solutions, I´ve finally decided to ask what do you think of.

I wanted to create lists of users that shares one or more relationships. But relationships that can be arranged by the site admin, some sort of lightweight group (without using OG, because I don´t need all the extra functionality that ir provides).
Doing this with flag or UR, is a pain (or maybe I didn´t managed how to do it).

Let´s say that I want to add some users to the group of people that have got their degree on 2007.

I want, when people visit a user profile, to see inside a block (Sidenote: I´m using the fantastic APK module) all other users that have got their degree in the same year. BUT, I want that block to show the current visited profile´s relation, NOT the logged in user relation.

So, let´s say I´m an outsider user from other school, that visits Jack´s profile.
Jack´s have got his degree on 2006, and he has achieved it in the same year as Martha and Sam.
So, when this John Doe outsider user visits Jack´s profile he sees beside Jack´s photo a block titled "Jack´s 2006 mates" and you can see there a picture to a link to their profiles, of Martha and Sam.

Jack didn´t added Martha and Sam as friends, or collegues, or nothing. He still can do that though.
The site tag all of them as "got a degree on 2006".

So I thought in two different ways of doing it:

# Adding a taxonomy to the content profile to each user. Something like:
When did you get your degree?
2005
2006
2007
# Another way could be to create a nodetype "degree", and add to the node "2007" several users, using a user reference field, where I should check all users that apply. That could be the easier solution, because I could add all users in one big fat step.

I need something that can be managed from the administration of the site exclusively.

Now the thing is that I don´t know how to achieve that block (or that view) in any of those two ways!

Any ideas? Maybe a third way? I´ve checked those "user tag" modules, but those are based on user´s likings, or visits... I need some sort of military imposition from the administrator ;)

Thanks for your thoughts and ideas!!

Rosamunda