You can have two different virtual servers and add required DNS records for the given domain against respective virtual server IP.
Lets say, you have created 10.10.10.10 and 10.10.10.11 virtual servers. Then bind DNS entries as given below,
xyz.com will be pointed to 10.10.10.10 and
abc.com will be pointed to 10.10.10.11
Both virtual server's pool will have same node with desired port.
Hope it helps!