Category 5 (lower tier, behind goals) officially all count as standing area although only Blocks 112/113 are actually terraced with no seats (however, for this area no day passes are handed out).
If you manage to get a hold of tickets for category 5 in the North, then all you do is agree on a meeting point once you've walked in with your passes in separate gates as your are free to go wherever you want. If you act witty and smart, even two tickets will be enough to get all 8 of you into the standing area.
Also, tickets will be cheaper at the stadium than over viagogo. When I want to have a laugh, I go on there to check out the exorbitant fees
