Along with a beacon, pack at least two avalanche shovels for a party of four. Better if you all carry one, but that might not be practical. It's also useful if your ski poles can be disassembled and used as avalanche probes. That's a common feature in Nordic poles, but not so common with Alpine ones. Even if you don't carry a beacon, do carry the shovels and poles.
The real key to avalanche safety is to avoid being hit by one. Get some instruction on how to judge whether a slope may or may not slide, then use that knowledge conservatively. About one-third of all avalanche victims die in the incident itself, so prudence is the main thing; the equipment you have on board will only come into play in the worst-case scenario.