Cacti collecting data from a remote system

[madkat]

Hello everybody!
I have the following setup: my monitoring machine which runs the Cacti instance (A) is NATted behind my router (B) which gets to the Internet through my ISP's gateway (C). I'd like to graph (for example using Advanced Ping ALT) the link between B and C (B pinging C) using the Cacti instance on A. Is it possible? and if yes, could anybody please point me in the right direction? In my particular case, A and B are Linux machines (and I guess C is a Linux machine also, not that it would matter). It would seem to me the poller (or an additional poller) would need to run on B when instructed to do so by A, and syphon all the data to A.
Any idea welcome. Thank you in advance!

Vlad