NAT question

Can iptables do a network to network nat without having to write out a 
bunch of nat rules.
In other words translate  192.168.198.0/24 to 172.16.10.0/24 without 
having to write out
256 rules.

Also can iptables handle 1000 nat rules like above if they have to be 
written out on
a 1.66ghz intel dual core atom with 1gb of mem.

I know this isn't appropriate question for devel list but I didn't find 
anything googling.

Thanks,

-- 

"They that give up essential liberty to obtain temporary safety,
deserve neither liberty nor safety."  (Ben Franklin)

"The course of history shows that as a government grows, liberty
decreases."  (Thomas Jefferson)