Create a "reactive global" variable with angular-meteor

I am trying to avoid using $rootScope to store a global variable, so I decided to put it in a service. In this case it’s currentOrganization which represents the user’s current organization. A user is only allowed a certain set of organizations and it’s stored in their user profile. I found out how to add that as a publication already, so I have the following:

{ 
  emails: ...
  profile: ...
  roles: [ ... ]
  organizations: [ ... ]
}

Now what I would like to do is somehow in AngularJS store the current organization which can be different across windows or browser sessions. Though I may change that if it isn’t generally possible.

One thought is to store it as part of the user object, but that would mean it will change across all browser sessions.

Another thought is to store it in $rootScope and reset it when the user logs in.

Another way I am thinking about doing it is to create a service/factory to store the data only on client side.

Still trying to get ideas and pro/con for each idea.

However, the key thing I have to watch out for is if I change users it should reset somehow.