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Can’t be be done with the stock installation and requires customization. Access is given to the entire catalog. As you will see in the admin there some aspects of the catalog that can be protected, but not individual catalog nodes.
Mirage is right, you’ll have to customize it - I don’t recall seeing anything like this posted so far so you’ll probably have to explore in the code or hire a programmer. You can always try posting your progress in search of feedback.
The only way to do it out of the box right now is to send them to different store views and only show the products in that store view - but that could end up with quite a few different store views depending on how many options you’re looking at.