Shaping 2 types of traffic?

[Sean Hafeez]

I am currently shaping all outbound and inbound user to 1mb via this:

ipfw add 999 divert natd all from any to any via rl0
ipfw add pipe 1 ip from any to any in recv rl1
ipfw add pipe 2 ip from any to any out xmit rl1
ipfw pipe 1 config mask src-ip 0xffffffff bw 1024kbits/s
ipfw pipe 2 config mask dst-ip 0xffffffff bw 1024kbits/s

rl0 is the external interface and rl1 in the internal.

Now what I would like to do is apply a different shaping for ICMP 
traffic while still limiting everyones individual total to 1mb. The 
reason for this is that we are having virus issues and I want to shape 
all ICMP to 64k vs. blocking it all.

Thanks!