This is feasible to config in WireGuard, but it’s somewhat up to the host to leverage it appropriately, and the config is certainly not clear about that fact. If you append the DNS config of a peer with the search domains you want sent over the private horizon (eg: 192.168.1.10, 192.168.1.11, internal.domain, other.domain) this is intended to configure conditional forwarding for those zones you specify. Again, it’s dependent on the peer host OS to be able to do that, but that’s how I do it with my client access VPN.