Restriction Groups for anonymous users

Our instance has multiple microsites and our current method of building our product catalog assigns each product to its category on every microsite. When users are logged in, we can correctly control the flow of presented products through Restriction Groups based on custom tags we have added to all products.

However, we would like to control the flow of presented items to each microsite based on custom tags. Since Restriction Groups only apply to logged in users, we cannot control which products are displayed on microsites without customization from our developer.

For example, using the same catalog:
Site A, all products visible logged out, restrictions when logged in
Site B, some products visible logged out, further restrictions when logged in
Site C, limited products visible logged out, more products visible logged in.