Route multiple WAN IP's through a L3 Switch

Five static IP's come into the MDF on fiber from the ISP. Would like one of the WAN IP's to appear on one switch port, and have a another WAN IP appear on another switch port. Then those ports would be plugged into a router/gateway or plugged directly into a server and distributed through other ports of the switch. Or the raw internet could appear on select multiple ports and whatever is plugged into the port could pull their static WAN IP. Is it possible using a L3 managed switch?

I'm trying to understand how this was done at a current install. The network cable from the ISP is currently going directly into a Dell PowerConnect 2724 managed switch. From there, the building HVAC system is getting one of the WAN IP's though the switch, the client's router is plugged into another port and is getting another WAN IP, then distributing it back into the switch. A tenant on the other side of the building is getting another WAN IP and then handling routing from their IDF with their own router. Unfortunately the original network architect is unknown and the switch is password protected. But it's working as intended. Now we're getting ready to upgrade the switches.

How do I replicate this setup with a new switch? How do I get the raw internet feed including the 5 static IP's to appear on various switch ports on a L3 switch? Guessing it may involve LAG and VLANs but wanted to ask before I start trying to figure out how to get it to work. Thank you.