Need help updating radio system

I am trying to update our 10 year student Skydiving radio radio needs to go on helmet or in it if I can find something small enough. I need something that has multiple channels. I need to have 3 of them on one frequency. The smaller and lighter the better. Any help would be appreciated.
Thank You

While I have not jumped out of a plane ever and especially never with any of my radios, I would first suggest a simple set of bubble pack radios (ones you can but at any local retailer) but if you have a license to operate on the business band (UHF/VHF) a set of Motorola Mag One BPR40s may be the way to go. If you are looking for something a little less expensive, the Baofeng UV line of radios have proven to be quite popular. I personally own a Baofeng UV3R for a year plus now and still love it. The radio is tiny and while it may not hold up to the same abuse a Motorola business model will it still is a hard radio to kill. Hope this helps!