[O] Include other sources (zotero, database) in org-mode search?

[Martin Beck]

I'm currently building a large knowledge database with my org-mode notes.
However there are other sources of knowledge like

- my colleciton of Freeplane mindmaps (xml files)
- my zotero Library

Is it possible to let org-mode also index and search such sources so that I
can search within all relevant sources (org and external) with ONE search?


Kind regards

MArtin