Homeplug over long distance

I am trying to push Homeplug adapters over its "normal" use, in a long distance powerline. Specifically TL-PA2010 AV200 adapters. Consider I have a energy line like:

A---B---C- - -

The distance between points A and C (AC) are beyond Homeplug capacity, but between AB and BC it works fine. In everypoint I put a Homeplug adapter and a WiFi OpenWRT router. Router in point A coects to WAN and have DHCP and others are just switch/repeater/dumb AP.

My idea is to use a intermediate router and Homeplug adapter as a "signal booster", but seems I am missing something.

The problem: Router in point C is able to ping router B, but not router A. Router B is able to ping router A and C. I think that is a limitation because input and output are in the same port of router B, due to nature of Homeplug mesh.

Any comment will be helpful. Thanks.