How can I bring these party ideas together?

Me and a good friend of mine share the same birthdates, and we decided to celebrate together. Our pals want a pool party and we want to give it to them... However, I wanted a Harry potter themed one and my friend wants a basketball themed party... Is it possible to consolidate all of these into one pool party that still has the "harry potter" and "basketball" element? Any ideas on how to do it?