Log in flow to multiple Firmex sites

Take this scenario:

You are the owner of two Firmex sites.
One is called Adelman Woods LLP (awlaw.firmex.com).
The other is Capital River Markets (capitalrivermarkets.firmex.com).

Some users have access to projects on the Adelman Woods site.
Some users have access to projects on the Capital River Markets site.
Some users have access to projects on both sites. 

Here is the log in flow for all users:

1. The user navigates to https://login.firmex.com/ or logs in via the "Login" button on Firmex.com.
2. The user enters their email address associated with Firmex and presses Next.
3. (If SSO is enabled, and the user is internal) The user is directed to their company's Identity Provider. They enter their password.
4. (If SSO is not enabled) The user is prompted to enter their Firmex password.
5. A user with access to both sites will be presented with a site list (below). A site will only appear on the list if the user has access to a project on the site.
   
6. A user with access to a single site - Capital River Markets, for example - will skip the site list screen and be directed to the Capital River Markets site. They won't know about the Adelman Woods site or be able to access it.