Afaik it can't be done. The mechanic just doesn't exist, you can't make it up. We don't have access to the engine, so we're really limited in what we can do.

I will argue however that if you have a full ring of 4 tiles radius of building, I think you don't need more "progress". That's over a hundred population required, which means roughly 400 turns (on standard speed) just to gather the population.

Start producing units instead :B.