Search only in a certain list of blogs/feeds


I have a list of certain blogs/feeds for a specific topic. I’d like to be able to let DA search only in those blogs/their archives. I tried to create a searchset containing all the urls. but this approach didn’t yield the expected results. another possibility would be to create plugins for every blog. but this seems a little inefficient, as many blogs have the same properties as many use the same technology.
in principle i would only need a couple of plugins with flexible/dynamic url, e.g. one plugin for blogspot-blogs with markers in the url that can during a search be dynamically replaced with the urls of the blogspot-hosted blogs of my list.
or search via technorati or another blog search engine, but with the possibility to somehow define a list of blogs were i want it to search.

which way will match my goal?

thanks in advance.