Custom Instant Messenger

I need a custom instant messenger made for a membership website. It must be able to integrate with my mysql database so only members can use the messenger, not guests. It must also provide multiple one to one conversations in one window. The user will be allowed to select which conversation they would like to see by selecting the particular member. Rather than have the people you are messaging with on the side laid out vertically it needs to be shown as a table(an actual table like one you would sit at) where you are on one side and on the other side is the members you are conversing with or empty slots for invites. It can have a limit of about 5 people. The messenger also needs to allow them to block the user they are talking too. The messenger also needs to have A/V option. I am flexible on what type of programming you would like to use and whether its in a browser or not.