Firewall-1 does address 'hiding' making it look to the external world
like all connects come from a single IP.
This should go to the "firewalls" list, I think. Anyway, Firewall-1
version 2.1 and later can do single ip to another ip address translation as
well as "hiding" many addresses on one side to make the all look like one
on the other. I have done this for my customers who have needed it and
wanted to use that product.