Can I prefilter a category through URL?

Yes. Under Catalogues > Your Catalogue, you should be able to retrieve the catalogue ID. With this value in hand you will be able to filter your catalogue. The URL should look like the following: www.yourdomain.com/catalogue-page/?categories=X Where X is the value of the catalogue ID, catalogue-page is the page your main catalog is displayed in. You can add more than one ID, in a commas-separated list, like the following: www.youdomain.com/catalogue-page/?categories=X,Y,Z