Hmmm... I´m guessing if you´re allied to the KH and they have both Massalia and Syrakousai that might work, though it´d be hard to arrange, and might require you to take those cities, letting them rebel and then Force Diplomacy an ceasefire and alliance with the KH. In a year or two when I´be finished all my other campaigns I might start a Romani campaign using house-rules similar to yours.