Create a player trading system

So my site is based on hockey and I am looking to create a player trading system that logged in GM's and submit trade requests to other teams. I have an admin login and each team has a login. for the team login we would need to make a spot on the menu that says "trade players" once you click on that I would like to see 2 columns one that lists all the teams players that are on the logged in team and in the other column have a drop down of teams or something like that and which ever team is selected show all that teams players. I am not sure of the best way for the GM would select players from his team and the other team for a trade request but we can figure that out. also would like to see a comment box so the GM can also put in other requests (ie- trade team points, draft picks) once this GM is done with the trade and submits it. it will send an email to the other GM and when he logs into the GM section for his team he/she will see the proposed trade. The GM will have 3 options (decline trade, accept trade and counter offer) -if trade declined send an email to the other user stating declined and maybe have a comment box so the GM declining can say why -if trade accepted send an email to the league admin and the other GM -if counter then make it so all the players from both teams show up in 2 columns and then he can submit it back ***there might be an easier and better solution to what i want but I hope this helps in what I am trying to accomplish :) any questions please ask. I want a programmer that will be able to have a great understanding of what I want and be able to work on it knowing what i want and not constant clarification.