I am not knowledgeable on that subject, but looking at the case of Louis XIV who kinda if I remember well imposed a relative to Spain (with a war ensuing, no?) - in theory, if the fortunes of those countries change maybe...
Or before and after, a royal daughter marriage... OR a different 'line' of the Hohenzellern kings, like the House of Valois and Bourbons to the Main Capetians... for another era of opportunity..