What your VMs doing on WAN? What a point have in 2019 Windows XP? FYI: in this year Windows 7 going to be off from support. Stop and move to fresh OS, especially this is VM, hell...
Firstly you say they on nat, then on wan. For me its looks like you even doesn't know what you have. How anybody will help you then?
Stop NAT all to internet, ESPECIALLY WindowsXP, you will hurt yourself. Configure OpenVPN and connect both VMs to one private network, and share what you want between them.