Ask HN: Applying to YC with a product competing a YC company

We have just passed out of college, and have built a B2B product which is in direct competition to a YC company. Our product has got really good traction in two months, with at least 8-10 big companies using it in private beta.

We want to be a part of YC and thinking of applying for W15 batch. Would it be a good idea? Is there a policy that prevents YC to accept companies in the same domain?