I'd like to hook on the existing search crawler process in SP 2013 and 2016 to use a 3rd party indexing and search solution. As a second step this index should be searchable by SharePoint as well.
I know the question is pretty unspecific, I just want to know if it is at all possible and what in general need to be done. Do I have to implement my own crawler? What's the keyword I can search for to get in depth information? The information I found were only on how to add 3rd party content to the SharePoint search. I'd like to do the opposite. Thanks for any hints!