buddy press activity loop, using the search_terms parameter….

I want to filter my activity loop to only contain blogs with certain keywords. Over here: http://codex.buddypress.org/developer/developer-docs/loops-reference/the-activity-stream-loop/

it says to use the search_terms parameter. I can only get this line of code to accept 1 keyword. I have a table of 20 keywords I want to filter the blogs by so that if they contain ANY of those keywords the blog should appear on my feed.

How do I do this?

Many thanks in advance,