Link in Emails

When a user gets an email notification, they see the "Unifier Login" button in that email. Can the link behind that button be pre-set to a specific URL?

We just launched SSO; but only for our internal company users and not our vendor users. What we have found is when our company users take action on a record that causes an email notification to be sent to a Vendor (Partner) user, the URL in the "Unifier Login" button is for our SSO URL; and not the URL our Vendors are to access. When a Vendor clicks on the button, they get a page cannot be found message.