If you're using a "real" search engine that crawl your site the information should be included unless you iframe it. If you're using episerver search there is no way to include those pressreleases unless you save each release as an epipage. Most people wouldn't want to create new epi-pages like that so the solution but if the place you get the pressreleases from has a search service you could modify your sites search to also issue the same search at the pressrelease provider and link the hits from there to your own site (you mentioned some id-thing). Another solution to avoid creating epi-pages is to store the press-releases in a SQL-table, activate free-text search and again modify the search-page to also search your SQL-table.