[support] Views: sort by arbitrary field value

Say I have a view that lists all the nodes on my site. Say I have three content types: page, news, blog. If I sort by content type, I can only sort by ascending or descending order: e.g. "blog, news, page" or "page, news, blog". What do I need to do if I want the articles to be sorted in an order of my choosing, say "news, blog, page"? (I guess I could create separate views for each content type and attach them, but what if I had thirty content types, say, and added more regularly)