Just rename one of them "Constantanople" and you'll be good.
This was a running gag in our campaign. Someone said "Istanbul", and my brother in law replied "Not Constantinople?" We all chuckled the first time.
The second time, he got a few tight lipped smiles.
By the fourth or fifth time we realized he was going to say it EVERY SINGLE TIME. And then it got funny again.
Late in the campaign, at one point someone said "Istanbul" and he wasn't paying attention. So the other three players just stopped and stared at him silently until he finally figured out what we were waiting for and said it.