Use Woocommerce Layered Nav Filters when attribute is NOT used for variation

Hi,

any hint about I can use any Layered Nav Filter when the attribute to filter for is not used as a variation to the product.
The attribute is just added as kind of a meta data to the product at best hope I can use this attribute as filter.
E.g. my catalogue has many similiar products in different colors but I set up every color as it’s own product, having only one color added to the product attribute ‘color’ and of course NOT set as ‘used for variations’ as it would make no sense when only one variation is available.
I wanted it to show a page where the user will be able to filter e.g. all blue products out of the whole catalogue

Thanks for directions
Tom