Route 53 IP-Based Routing

Yes, it is how to create IP based Routing record in Route 53, however my use cases are: Traffic flowing from CIDR block 192.168.8.0/24 goto Load balancer Endpoint A, While every other traffic flowing from any ip address goto Load Balancer Endpoint B.

I forgot the limitation "You cannot use IP-based routing policy for records in a private hosted zone.". Then where is the network 192.168.8.0/24? In on-premises DC (external from AWS) or AWS VPC? If on-premises DC, you can consider to utilize DNS related functions in on-premises resources. If AWS VPC and it is different from other clients' VPC, you can use different DNS hostzone.

If you can and "Load Balancer" means ALB, then, you can use IP based routing rule of ALB (but, you need to use same ALB for all client)

I just use the 192.168.8.0/24 as example, that is not the main IP to be used, The main IP is a Public CIDR OF from set of users within an organisation to be routed to Endpoint A, while any other traffic from around the World to be routed to Endpoint B.

Then, you would be better to refer following (same with what I said above). You would be able to validate the process by your internal AWS account. https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy-ipbased.html https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/resource-record-sets-creating.html