PMR446 / WALKIE TALKIES

Hello, This project is for a small PMR446 (or similar) Walkie Talkie, but I only want ONE-WAY communication. I need one receiving unit to be worn by my customer which receives voice transmission only via an earpiece - no internal speaker is wanted. It must be a very small circuit that I can mount into a protective case. The other transmitting unit must be able to transmit voice to the receiving unit and size is not so important for this unit. Ideally, I would want my one transmitter unit to be capable of transmitting up to six independant receiving units - all on their own channel. (Maybe an 8 channel unit?) This would enable me to have private conversations with up to six different people if required. I only need a transmission range of approximately 100 metres for this system, but vocal transmission and reception has to be very clear and of the highest quality, as the units will be used in a noisy environment. I do need to be able to legally use this unit in the United Kingdom. The receiving unit must be as small as possible, so power for the circuitry must come from a small battery. Or perhaps it could be made re-chargeable? I hope that we can do business together, thank you for your interest in this project. Martin