Exactly that buddy. Too many lines in one area. I see this a lot, particularly in France where they're always pressured.
I watched a couple of mates do this to very good effect (on a French trip funnily enough). Pretty much as you say; both baiting towards a central area, both fishing to their near side of that area. What would happen is one of them would pick up a fish or 3 then they'd back off. Shortly after the other would have a couple on the bank..... and so on and so forth. They bounced those fish off one another for a week, kept the bait going in, and they ended up with a very good tally of fish as you can imagine (including some proper units).