On DreamPress, no. We don't support multiple blogs on one instance of DreamPress at this time. (Yes, that includes Multisite, which would normally be my suggestion for this.)
But... I would recommend you actually use categories for this instead.
Unless these all really need to be totally separate sites (different admins, different plugins, different themes), you'll save yourself a lot of heartache by using categories instead You can even tweak WP so you don't have domain.com/category/photography if you wanted. The added bonus is also that you only have one place to login and make your updates and edits and everything else.
Works pretty darn well