Hi all. The organization I work at bought a new service (medical library) from a provider, that in order to give acces to its services, wants to see the requests coming from a specific public IP. Unfortunately our ISP can not provide us with a unique public IP, but can only implement a NAT from an internal IP (e.g. 10.169.93.207) to a unique public IP. So, I want to redirect all traffic from the internal network going to a specific address (e.g. 60.130.31.45), to an internal IP (10.169.93.207) which is tied to a unique public IP from my ISP, that is recognizable from the service provider so he allows the access. Thanks.

If you are behind a CGNAT you are mostly out of luck, there are few ways to overcome this with various degree of hassle / difficulty on your part

option A

first get a business line and ask your ISP to provide you /30 or /29 V4 address or even better get IPV6 address allocation

option B

pop a VM to any cloud provider you desire and established a VPN from there and do appropriate routing

One option is to procure a cloud server, can get them cheap in the USE like $6 A MONTh. Then route all users at work with need to access library through a wireguard tunnel to the CHR and out the internet that way ( KNOWN FIXED PUBLIC ip )

You will need to mangle LAN traffic destined for medical services out wireguard.
Can you identify the request to go to medical services by anything specific, fixed public IP address, port number etc.............

Don't know if I understand exactly your scenery, but there you go: