I think it is:
openvpn client 1 <---> openvpn server <---> openvpn client 2
Can I connect to client 2 from client 1 directly? like this:
openvpn client 1 <-----> openvpn client 2
This is mesh networking. Support is anticipated at some point in the
future (OpenVPN 3.0 or 3.5). There's been extensive discussion on the
topic on the mailing list; feel free to browse the archives.