[Koha] How to link Koha with another software

Dear all We have got a user database with lots of other things (invoices etc) on Filemaker Pro, in one part of our organisation. We would like to automatically link that user database with our Koha patrons database -- so when we update the user database on Filemaker it automatically updates our Koha patrons database. Does that exist? I tried to look for it in the manual (and other places online) but I probably don't look for the right words, I am not sure what to search... Cheers, Sonia.