Redirect public ip

My public IP is for example:

152.231.88.100 / 29

I have 5 IP available. (1 for the router)

I get 4 IP to distribute, but not for all customers.

Eth1: Internet (152.231.88.101)
Eth0: LAN (10.10.10.0)
Eth2: LAN2 (public ip distribute 4 remaining)


Any idea how to divide 4 by the Eth2 public ip?

regards and thanks you.