Indeed, HtmlFormatProvider and HtmlDataProvider are the classes you should use if you want to import HTML content in RadRichTextBox. However, they do not expose API
that can help you in achieving your goal.
One possible resolution would be to subscribe to the DocumentChanged event of RadRichTextBox and handle the cases which you want to exclude - i.e. remove
all hyperlinks pointing to an external location from the RadDocument.
However, I believe the best approach to implement your scenario would be to preprocess
the document before executing the import. You can do so in various different ways, for example using regular expressions. You should be aware that all scripts in the file will be excluded on importing, so they do not need additional processing.
I hope this helps!
All the best,