Application layer firewall on FreeBSD, is it possible ?

Hi all,
 
let me ask you for task "how to control p2p applications and their traffic
with dynamic ports from user´s commputers on gateway".
 
We are small wireless community and have shared access to internet for all
members. Core members decided to control p2p traffic by default and to allow
each person in individual way,
after showing their knowledge of authorial low. :)
 
But since many dc hubs, edonkey servers, bittorents web trackers and so on
use dynamic not standard ports, how to control it ?
 
Linux use l7-filter http://sourceforge.net/projects/l7-filter sourceforge
freeware and , it is based on iptables, defination application protocols
like ethereal project do.
 
So, is there any way to do same application layer osi model firewall with
FreeBSD gateway ?
 
Of course, I tried to find on web, I have not been successful in searching
so far.
 
If my question is not right in this mailing list, if my question is annoying
here, so I am sorry.
 
Dan