It sounds like an XY problem. What is it for?

a concerned citizen‭ I'm going out slightly on a limb and assuming that it's for fun.

I'm not going to answer until you explain the larger problem this fits into. You have abused the volunteers here with very unusual requirements that you simply dreamed up, and that would not present themselves in a real world situation. Either explain the real-world problem you are facing, or mention that these are just arbitrarily made-up requirements.

It is a exercise I made up to learn about filters.

Don't tell me here. Put that in the question so everyone can see what is really going on.