Well, typical American/New World/CA merlot is pretty soft and low-acid, whereas typical Chianti is pretty high acid. So, in that case this might be a new type of wine for your relatives.
Of course much could depend on the vintage (03 and 05 were hot years so the Chianti from those years is lower in acid) and also on the winemaking. Perhaps you could post more details, i.e. the vintage and the producer?
If you want something that is more in line with the "typical" CA palate you might look for wines from Southern Italy, which tend to be richer.
But, that doesn't mean you shouldn't also stick with the Chianti, exploration can be fun
