Random Pair Generation with Multiple Criteria (index/match)

Hello everyone,

I am having an excel formula problem, and it would be greatly appreciated if you could help me out.
Long story short, here is my attached document.


I am trying to create a list of random pairs with this criteria:
Criteria
1) Two people to be paired up randomly, but
2) Two people to be from the SAME cluster (Same Cluster Code)
3) Two people to be from the DIFFERENT department (Different Department Code)
4) Should be automatic calculation -no manual rand() sorting



but the problem is, it keeps showing me duplicate. For example,
If Frederica and Rosie are paired up, then Cristen should not be matched with Rosie, etc.

Please help!