How to add a route for VPN traffic?

Our sales agents must access a 3rd party website on the net that we use to process credit card orders. The website is IP restricted for security, so users in the office are fine because our static IP is on the site’s approved list.

Remote users are unable to access the order processing site unless they connect to our VPN and check “Use default gateway on remote network” in the advanced VPN settings.

This passes all their internet traffic through us and allows them to get to the ordering site, but it’s really slow.

If I disable “Use default gateway on remote network,” to speed up the VPN, can I add a route for the ordering website so that just traffic to that site passes through the VPN gateway?