If you want some local systems to always connect to the vpn. use this dnsmasq setting.
please change the mac addesss the ip address the hostname and the vpn_gateway IP.
dhcp-host=XX:XX:XX:XX:XX:XX,set:localvpn,192.168.X.X,myhostname
dhcp-option=tag:cpxhosts,option:dns-server,8.8.8.8,8.8.4.4
dhcp-option=tag:cpxhosts,option:router,vpn_gateway