Hello everyone and thank you for your comments ahead of time.

I have a Fiber ethernet connection from Comcast that is a layer 3.
I like to know if its possible with IPTABLES to create a firewall router with it using these parameters.

ISP: Layer 3 P2P /30
Gateway: 51.226.133.1
Netmask: 255.255.255.252
Layer 3 usable IP customer end: 51.226.133.2

ISP NAT POOL: /27
Range: 51.226.132.224/27
Usable Range: 51.226.132.225-254
Netmask: 255.255.255.224

Private Network IPs:
172.30.0.x/22 (Separate switch)
10.30.0.x/22 (Separate switch)
10.1.1.x/22 (Separate switch)

System Network adapters:
eth0(51.226.133.2)ISP
eth1(172.30.0.1)Network1
eth2(10.30.0.1)Network2
eth3(10.1.1.1)Office

So I can get IPTABLES to work with the first part but cant find information on the NAT Pool.
The NAT Pool will map to various resources www dns sftp ect....
Looking for a clean approach.
Thoughts?

Yes, it's possible. NAT is a table in iptables. It is used for exactly what you want to do. Here's an explanation of how to use it: https://www.karlrupp.net/en/computer/nat_tutorial