indexing external sites urls

[gg4u]

Hello,

I am building a site to visualise correlations in a db.

The core of the service is not textual search, and I would like to delegate this functionality.

Is it possible to use custom search to index external sites urls, so to use it as entry point to my site?

As example, possible to index wikipedia pages and then use the resulting db, giving in output the name of the corresponding url or page?

I've seen a mobile app (wikiwand) use a custom search applied to wikipedia-

I would like to have something like this:

MY_DB indexes web objects of  domain A (by _url or _id)

Custom_SEARCH_DB index domain A (textual search over web pages)

I can then update Custom_SEARCH_DB with my own indexing, as use it as entry point to find the _ID object to query MY_DB