They have an app now to add Jamaican Area Code.. I've not personally used it so I can't give feedback.. somebody here can install and test and report back...
https://play.google.com/store/apps/d...m.mobile.jcode
It seems as if the app is going to add +1876 vs just adding 876 ... I've just been manually adding 876 as to me it looks cleaner than +1876