A Company specific portal is quite a common request in multi-company environment.

If you create multiple companies and one website for each, with separate domains for each, and associate each website with the correct domain, Odoo will automatically show the correct one based on which domain was used to connect to the server.

If you have these Companies:

• cat
• dog

These websites:

• cat 
• dog

These domains:

• cat.com
• dog.com

You can connect them all together so when someone visits cat.com they see the cat website and the documents from the cat company - all with the same portal account.

To do this:

• have NO COMPANY set on the Contact record of your Customer
• set ALLOWED COMPANIES to both companies on the User (Portal) account

With other configurations, it is possible to tie a specific Contact to a specific website

More details:

Install the website application.

Create a website per company. If the company does not have a website, unpublish all the pages of the website.

Enable Developer mode by going into general settings scrolling all the way to the bottom and activating developer mode.

Go to Website -> Configuration -> Websites.

Add the domains for each company on the corresponding websites.

Add the companies to their respective websites. and save the changes.

Go to Website -> Configuration -> Settings.

Select one website

Check that "SHARED CUSTOMER ACCOUNTS" is checked, which is the default

Repeat it for all websites.

When a new user signs up on a specific website, they will become a portal user for just that website and they can use the same email and login as a portal user to the second website as well.

The contact associated to the user record on the backend CAN have the website specified on it making it specific to a website IF YOU NEED to restrict SOME Customers from having access to ALL websites.

If you DO NOT set a value here, they can log into ALL websites, provided you give them permission to log into all Companies

With either option, all records tied to a Company like orders, invoices, projects, etc., that are will only be visible in the portal of that company.

This means the Customer with a single account can log into cat.com and see their orders from that company and can log into dog.com and see their orders from that company - without seeing both at any time.