Public Website (CMS) accessing content from Sharepoint Online

We are suffering from duplicated content across our O365 Sharepoint Document Libraries and the School's Public WebSite.

For example, a policy on SunSmart Awareness exists and is well maintained within our Sharepoint Document Library; however, the marketting department download a copy and upload it to the "public website" within the structure they maintain.  6 months, 12 months, 3 years later... we discover the parents have been accessing and referring to a document that has been reviewed updated on Sharepoint.  etc etc...

I'm sure we all experience it?  Are there any web platforms out there that will allow a plug and play into Sharepoint Document Libraries - I'm assuming by utilising an authentication token of some kind?

Thanks for any advice.