Facebook sharing for multi tenant web application

I have a multi-tenant web application and I'm wondering which would be the best way to let all the tenant publish their content on the feed of their facebook page (if they have one of course). There's no public page/link to share so all the shared content has to go straight to the feed (using JS with FB.api feed + photos...). I am wondering which is the most proper way to accomplish this task: having one FB app for every tenant, or using the same FB app for all the different pages, or some other way... Any suggestions?