[LARTC] "interactive" traffic shaping

[dp]

Hi!

I'm trying to control the bandwidth usage of a filesharing client.
I've read a little bit of the LARTC HOWTO, but I'm not sure it gives me the 
solution, or I can't see how it could give one. 
I was thinking about the possibility to run the application in an "artificial 
environment" (relatively to the user's one) where all connections are slowed 
down. 
In the howto I red about limiting the bw of an host connected to a network; is 
it possible to run a process on a "virtual host" (without effectively being 
on another computer), with its own address and in a sort of LAN with the real 
one, so I can limit the bw of that virtual host?
As I said, I'm a newbie, and maybe I'm saying things that just can't exists; 
but if there is a way, can someone please tell me where to search or to read 
(I understand that maybe a full answer would be too long, and maybe it would 
be a useless doble work). 
Thaks!
Daniele P.