Redirect when the client address is not equal to the networks in datagroup

Try this

-Modify "original_pool" to the default Pool name for the VIP

when HTTP_REQUEST {
set host [string tolower [HTTP::host]]
if {![ class match $host equals XYZ_group ] } {
   HTTP::respond 301 Location "http://rextrum.com/xyz" }
  else 
  { pool original_pool }
}