Create 2 different iRules for Redirection

Okay, this should be closer to your description:

when HTTP_REQUEST {
    if { [class match [string tolower [HTTP::host]] ends_with my_uri_dg] } {
         in the data group
        HTTP::respond 302 Location "http://www.yourwork.com"
    } else {
         not in the data group
        if { not ( [string tolower [HTTP::host]] starts_with "www." ) and not ( [string tolower [HTTP::host]] starts_with "myworkplace" ) } {
             not in datagroup, not start with www and not start with myworkplace
            HTTP::redirect "http://www.[HTTP::host][HTTP::uri]"
        } else {
             doesn't match any conditions
            return
        }
    }
}