Registration of new user for client site

I configured the Events+ on a subsite when the member clicks to join the event, the member is sent to the default WordPress login form, when clicked on Register button, it redirects to the primary domain instead subsite.

I'm wondering if possible to modify the register/login button on Event+ plugin so it could be redirected to a custom registration form, or maybe to Membership 2 Pro login page, once I use this plugin on my subsite too.