Serving multiple customers in one FileMaker file is a powerful option.
This way upgrading / adding new features are better manageable.
It would be very powerful if we would be able to divide the total dataset in all tables by an global setting. OrganisationID or something like that. Under the hood filemaker marks every record added/modified by an account with this organisationID. Every things works as in an 'normal' solutions. So we do not have to set view rights or filter portals etc..
Kind of a global data separator.
This is important so we FileMaker grows towards SAAS with Webdirect. Updating becomes more manageable.
We only have to update the server and one filemaker database file.