Whenever anyone has hiccups around me, I do the following:
Get serious about the situation, way more serious than one would otherwise get. Have them sit down and explain to them clearly that they need to concentrate very hard and let me know just before they hiccup that they're about to hiccup. So they sit there for about fifteen seconds, getting really embarrassed because they're all "LOL I Don't know! This is hard!", all the while, without hiccuping. Soon thereafter, they're all, "I think they're gone?" to which I respond, "Exactly."