About pipe

[Yavuz Maşlak]

I use pipe ( dummynet ) with ipfw for bandwidth on freebsd8

There is a  /24 ip blok which is 192.168.1.1 - 254 .

I pipe them at 20 Mbps. There is an special ip ( 192.168.1.100 ) in it.

I would like to allow this ip at 10 Mbps.  The 10 mbps is in the 20 mbps. 

If the ip doesn't use any usage, I 'd like to be  All of 20 mbps can be used
by the other ips ( 192.168.1.0/24 ) 

How can I do that ? 

Thanks