Exclude IP from routing through VPN

[lucamoscatofun]

Hi all,
we have a funny issue here. pfSense/OpenVPN server route all the company network(s) such as offices networks, servers and client connected to vpn. We can summarize all networks with 172.16.0.0/12 but ... there is a printer in the office :)
Actually I can't reach it if I'm connected to vpn, so that I'm searching, server side, a way to exclude route for that specific IP.
Going here and there I found that I have to add an additional options, in my case in my client specific override, such as
push "route 172.18.XXX.XXX 255.255.255.255 net_gateway"
in order to tell the client, do not route that IP in our vpn, use your net gateway, but is seems not working.

Any advice?
Thx