Thanks Earleene for the info on the Irish Gasses - I suspect that illustrates that there is not a connection between the Irish and the Swiss that go by this name, unless, of course, it could be demonstrated that the Swiss Gasses in fact descend from the Irish. I have no information on the origin of the name in Switzerland.
Perhaps some family names in Ireland could provide a clue? Amongst those in Switzerland feature names like Johann, George, Paul, Ferdinand, Frederick and even the odd Sebastian! Do any of these match with first names amongst the Irish Gasses?