Product filters with multiple select

Hi, Is it possible to let the visitor filter the list of products based on multiple values from one particular filter.



So, assume a product filter “brand” with possible values like “mercedes”, “BMW”, “Audi”, “Chevrolet”, …

The visitor is interested in “mercedes” and “audi”, so he wants to filter on those two brands.

The resulting product list should only contain products of those two brands.



By default you can only select one value and you need to reset the filter to select another brand value.



Is this possible? If so, could some one point me into the right direction?

If not, is there any addon that could do this trick?



Thanx in advance for your reply!