Could route add vpn to do?

[akong77]

My network like follow
                                                                   These server and client are the same server
|Windows Wireguard VPN client|--->|A:Wireguard VPN Server|+|C:Wireguard VPN Client|--->|B:Wireguard Server|
            Wireguard IP:10.8.0.2                           IP:10.8.0.1                   IP:10.7.0.2                        IP:10.7.0.1
I can connect from Windows Wireguard VPN client to A wireguard vpn server and C wireguard client also can connect to B server.I hope windows client through A server and forward to B server then go to internet.But Windows only ping 10.8.0.0 network.I try setup C client allow ips add 10.8.0.0/24.But it's can't up this interface when I add allow ips 10.8.0.0/24.Could any friend teach me how to do it?