We currently have our setup configured with our ISP router as the gateway
(ie and our next address .250 as our firewall that does
NAT for the rest of our boxes 251-254.

We currently need another IP address for hosting and our ISP provided us
with two separate addresses, ie & .70. They said they have
applied .69 to our existing router and we are free to use .70. When I
asked how to apply the address, he asked if our Firewall (BM38) can have
more than one range applied to it?

So can BM have a secondary IP address of applied to it,
so .70 can be used for the NAT on the internal box which he said is
probably the best way to do it?

I hope I am making sense anyway and someone can point me in the right