how to create the iRule for redirecting traffic on URL context string?

You can do this with code like the following. As long as people are accessing the URL by ip address like in your example, it should work. Otherwise, You'll need to add some additional conditions in the switch statement to handle the alternate hosts.

when HTTP_REQUEST {
    switch -glob -- [string tolower "[HTTP::host][HTTP::uri]"] {
        "192.168.10.1/YYYY*" -
        "10.10.10.1/YYYY*" {
            pool YYYY.YYYYY.com-https 
        }
        "192.168.10.1/WWWW-*" -
        "10.10.10.1/WWWW-*" -
        "192.168.10.1/VVVV-*" -
        "10.10.10.1/VVVV-*" {
            pool YYYY.WW.YYYYY.com-https 
        }
    }
}