net-snmp and mrtg question

[Angelin Lalev]

I have FreeBSD router with two interfaces. Every interface has several 
networks.
The basic configuration of snmpd and mrtg allow me to monitor the
load only on per-interface basis, but I need to be able to monitor the 
traffic
on each network separately.
Is there a way to do it via net-snmp / mrtg?
Are there orther tools with output similar to mrtg (prefferably the 
same), which can do this?

TIA