So I have a mixed security model that has the appearance of having 3 different portals;
1. Public --> Collab to ArcGIS Online
2. Secure --> Custom Applications
3. Internal --> Internal\Sensitive
So is there a functional/technical reason why I can't have 3 different portal instances all hosting to the same ArcGIS Server site? Based on what I see in the docs; there should not be a issue.