Default page display

I am talking with a client who wants his default page to only display designated posts. I was thinking that this could be done simply by going into Settings > Reading, but I see that only Pages can be chosen from a drop-down there. Is there a way to enter a URL as the default home page (e.g. yourdomain.com/path/?cat=X or yourdomain.com/path/?tag=X)? If so, he would be able to do this simply by adding a certain tag to those posts, or by putting them in a designated category.

Thanks