rediecting site to different page but on same pool member..possible?

Exactly where you want to change the URI is unclear, so this is a guess;

when HTTP_REQUEST {
  log local0. "Request: [HTTP::uri]"
  if { [string tolower [HTTP::host]] equals "abc.com" && [HTTP::uri] equals "/default.aspx" } {
  log local0. "sending request to error_aspx"
  HTTP::uri "/error.aspx"
  } else {
  log local0. "sending request to pool"
  pool abc.com
  }
}