Well, with the aforementioned music etc I'm sure you could pull together and have a whispered convo that no one else can overhear, but that's a good question all the same.
Maybe to have a party-wide telepathic conversation you/the psion have to part with 1HP, as if it was an Empower ability? Just so there's some sort of investment or cost, otherwise there'd be no reason not to use it constantly. And in turn removing that cost and/or greatly increasing broadcast range would be good fodder for a passive aspect ability, haha
But for parity I imagine Tech can allow for the same thing: that is, long range communication that eavesdroppers aren't made privy to