Assigning user to certain company in Navision

Navision allows It's users to entry data for multiple company. But how to set one user in order able to entry for eg. 2 companies ? To do so, for every permission that assigned to that user needs to select the company name. By default the company name is blank.  It means can access to all company.

The moment you put in company name means the user can only access to that company. Eg. You create a user named WI and you grant him permission Super (data) to company LIVE-BUT.  This means, user WI only applicable for company LIVE-BUT.

If user WI also need this permission for company Live-MB , then It means need to add another permission line Super(data) and select the company Live-MB.

You might want to put this control only for those users that need to limit them. For super user leave it as blank company will be easier to manage.