Limiting the port range

Is there any way to limit the port range with which rtorrent talks to other clients?

These are my current settings:

$scgi_port = 18501;

network.port_random.set = no
network.port_range.set = 18500-18500
network.scgi.open_port = localhost:18501

This is what I’d like to limit to a specific range:

rtorrent 7338 x 65u IPv4 33395 0t0 TCP my.ip:38580->c-their.ip:55936 (ESTABLISHED)
rtorrent 7338 x 66u IPv4 33396 0t0 TCP my.ip:53400->dhcp-their.ip:48733 (ESTABLISHED)