I have a question about connectors

Imagine I have three objects, A, B, & C and they're connected in series like so:

A---B---C

Here's my problem: If I move A, the A-B line adjusts properly. If I move B, both the A-B and B-C lines adjust properly. If I move C, the B-C line does NOT adjust -- the C end is just left hanging out there attached to nothing. It's as if there's a one-way relationship between B and C. I want it to be a two-way relationship.

Can anyone tell me what's going on there? Maybe I'm not attaching the connectors right in the first place. I've hit a dead end trying to understand it on my own.

Thanks!