parse cookie content company code to specific pools?

A cookie is generally a key-value pair, so is the A1, B1, C1 a key or a value?

For example, if it's a value (assuming the cookie name is "COMPANY_CODE"):

when HTTP_REQUEST {
    switch { [HTTP::cookie "COMPANY_CODE"] } {
        "A1" { pool POOL1 } 
        "B1" { pool POOL2 }
        "C1" { pool POOL3 }
        default { reject }
    }
}

Of course this doesn't work if the cookie is passed AFTER the initial request. Do you have an out-of-band mechanism to distribute the cookies, or will the user connection initially without the cookie and hope to get one at some point?