Aperture retrieves a hierarchical database of places from the net as you use it. This breaks down each place into countries, states, cities, and places.

As a result, you should only need to assign places to each local group of photos. This should allow you to use the path navigator in the Places tool to select all photos in a given country or region.

To assign places, go to the Places tool and zoom into the area you are interested in. Select one or more photos and drag them to a point on the map. If you're happy you have the right point, click the Done button, and each photo should be marked with a small red pin icon.

For example, if you have a folder containing all photos in Mumbai, you can drag those photos to Mumbai in the map in the Places tool. Similarly, any photos taken in Hyderabad should be dragged to the map. You should then be able to ask the Places tool to show you all photos in India, which should include both of those groups of photos.

You can also then create a smart album for a particular area of the map:

1. Scale the map so it only shows the area you're interested in. You can do this by holding down the command key and dragging a selection rectangle around the pins in your area, or by just zooming and panning the map.
2. At the bottom of the map, click on the Action menu button (looks like a cog). Choose "New Smart Album from View"
3. Rename the Smart Album to be something suitable (e.g. India)

Alternatively, the Smart Album HUD allows you to choose a specific place.

1. Create a new Smart Album
2. Click on the Add Rule menu and choose Place
3. Select the Place checkbox and type "India" (or other place name known to Aperture)
4. Name the Smart Album as appropriate