Generating per-ip SNMP network data with linux box

[Darknight]

Basically I have a linux box configured as a bridge between my network and the outside world. Since it is in the perfect position to collect network data I would like to use mrtg to generate nice graphs about my hosts (not about the whole network, that's already done upstream). What I need is exactly the kind of data mrtg displays: bandwidth usage history with good granularity.
I need to find a way to feed the data to mrtg and I wonder if snmpd could be the right tool and a hint about how to configure it to achieve my goal.
I hope I've been clear, I'd like to understand if my idea is feasible before I spend a lot of time studying documentation.
Maybe I'm looking in the wrong direction, any help is welcome.