使用相同的应用程序而使用多个域ASP的单标志。NET MVC

we are trying to implement single sign on, across multiple domains, but using the same web application under IIS. We have checked some solutions like SAML and OAuth however we are not sure we need anyone of these two. We dont know how we could share the cookie accross the domains, I dont think it's possible but correct me if I'm wrong.we are trying to implement single sign on, acro