Triangle? No, tetrahedron.
I'd say it's not quite accurate to say a,b,and c are linked simply as a+b+c=abc; abc is its own entity, and not only do a,b,and c each have their own relationship with abc, but so do "base pairs" a+b, a+c and b+c.
When you have the right mix of personalities, it's truly wonderful...but it's a lot more complicated (and less stable) than a simple pairing. I can't even imagine what headache bottling plants 4-ways (or more) must be.