Simple Reverse Proxy

In tmsh it would look something like this (which probably makes it look more complicated that it is;

ltm data-group internal host-data-group {
    records {
        example1.com {
         pool-1
        }
        exmple2.org {
         pool-2
        }
    }
    type string
}

Menu path: Local Traffic > iRules > Data Group List > Create > Type: String

Add records with the domain name as the String and the Pool name as the Value.