How to assign multiple pools to single virtual server [VIP] in F5

Solution 1:

Dexirian is correct above - but I think this more correctly answers based on your need for multiple pools due to multiple clients:

when HTTP_REQUEST {
    switch -glob [string tolower [HTTP::uri]] {
        "/123*" { 
            HTTP::uri "/"
            pool pool_123 
        }
        "/456*" { 
            HTTP::uri "/"
            pool pool_456 
        }
        "/789*" { 
            HTTP::uri "/"
            pool pool_789 
        }
    }
}