Menu Links & Duplicate Content

Hi!

I have a business website wherein pages of different product lines have to be published on different subdomains. For example, valves will go on valves.example.com and glasses will go on glasses.example.com. I require the menu links to these product pages available across all domains. However, the pages should be accessible only from their respective domains. For example Gate Valve should only be accessible from valves.example.com/gate-valves and not from example.com/gate-valves and glasses.example.com/gate-valves. When I select "Send to all affiliates" it is accessible from all domains and when it is deselected it does not appear in the menu of other domains except that of the domain on which it is published.

Your quick help would be highly appreciated.