Custom plugin for game server

I Run a game server which i would like to create a custom feature for but i do not have the skills to do so. I want to add a feature which will allow users that join the game server to upon their request teleport to a random position within an area on the map. I would also like to add a function which changes the chat system and allows people within a radius of each other to see a local chat (proximity chat) and then be able to use a command to speak in a global chat.