It would be good to have similar functionality like uTorrent provides with isp.peer_policy_url property.
The format is the following:
<iprange start="10.0.0.0" end="10.255.255.255" weight="10" />
<iprange start="172.16.0.0" end="172.16.255.255" weight="10" />
Here is actually the way to say bittorrent client where to find peers firstly.
It's pretty good for users as well as for ISPs to keep bittorrent traffic inside of ISP's network.