Build a Push-To-Talk Voice Communication Software

I need someone to build a push-to-talk voice communication client that will allow multiple users to "join a server" by entering the name of the server in... The system would then check our mysql database to see if that's an active server and see who is online and see if the maximum number of users that can communicate is filled. If the server exists and there is room the user would then see a list of everyone in the server. The user would be able to join various channels to speak to the people in those, change the key they press to talk and would be able to hear anyone else talking in their current channel. Users with "admin permissions" would be able to ban, mute or suspend user's access to the server or just kick them off. The client side needs to run on windows and it can run inside a browser (IE java or flash) and will need to run on a linux server preferably centos or debian... Building this in java would probably be the easiest method because its the fastest to work on multiple platforms. However if you can build this using c++ or python and have it run on both platforms that'd be awesome. The idea would be to have one "server" running that connects all of the users, but make it so that only users in specific "areas" or "server sections" can hear eachother. The other option is to have one server instance launch for each real server, which would be fine as well assuming it can be programmed to allow access from multiple ports.