Sync exchange with local calendar WITHOUT granting permissions to gmail or Samsung

It's pretty simple, what I want, I think: - 1 local/offline-only calendar on the phone (default Samsung app) - 1 on-line exchange calendar (automatically synced) - ability to show one or the other or both at the same time in the same view - notifications coming from both calendars, as if they're both local I do NOT want: - to associate a google account with the phone - the gmail app to be in any way involved - to accept Samsung's request to hold my personal information for 5 years on their servers - any kind of sync involving e-mail, contacts etc etc. It amazes me that this seems nearly impossible to do. Is it/how?