Ok here is why what you ask is not possible even to have a “small ping difference”. Well actually, I suppose you have to define what you mean by “small”. Do you mean less than 10 or less than 30 or less than 50 ping difference on average.
When I had a server in New Jersey (east coast of the U.S.), people on the West Coast of the U.S. with good cable connections had pings of about 70 on that server. People from England with very good cable connections pinged about 110 on that server. Most are about 120 ping. I have DSL (slower than cable) and I ping 15-20 on a New Jersey server because I live in New York, the next state over. People in the mid west (Miichigan for example) ping about 40 on an East coast server.
Ping is dependant not only on what type of internet connection you have, but mostly on the DISTANCE you are from the server. So unless you are going to play only people from the West Coast on an East Coast server you wont EVER have a small difference in ping on average and at best that difference would be about 30-40 average. If you have players from the mid west and east coast, the difference increases.
Even though the electronic age has made the world closer in the digital world, we still have not been able to make the continents and countries closer together in the physical world. In the words of Mr Scotty “You can not change the laws of physics!”