iRule to allow one of two URIs block all others

I wouldn't both with a data group if there are only two URIs involved. I'd use something like this. You can remove the logging once it tests out OK;

when HTTP_REQUEST {
  switch [string tolower [HTTP::uri]] { 
    "/system/templates/selfservice/sunburst/!portal/240100000001001" {
      Stop processing the iRule for this event here
      log local0. "Match on 240100000001001"
      return
    }
    "/system/templates/selfservice/sunburst/!portal/240100000001002" {
      Stop processing the iRule for this event here
      log local0. "Match on 240100000001002"
      return
    }
    "default" {
    drop
    }
  }
}

If you don't see a match, perhaps its to do with the

!