Crossing bred like that, tha were bred for completely different work, would likely take a lot of generations and careful breeding before anything stable was achieved.
Not that you won’t end up with an awesome dog, but you could likely get a whole bunch of pups that just don’t do what you’re looking for.
Crossing pointer breeds, herding breeds, retrievers.......go for it. They all share similar instincts. Cur and a shepherd? It’ll be a crap shoot.
Still, go for it and report back!
“Life is life and fun is fun, but it's all so quiet when the goldfish die.”