Meetup and Email List site

I would like to create a site where people can organize events and send emails to groups of people. The final functionality of the site will include the following. A user can login and create a "group." A group is a list of people's names and email addresses. The person that created the group can organize events which all group members can be invited to. There will be messages (or "comments") associated with each event. There will be comments associated with each group. The site would be run on Wordpress and the functionality would be done in PHP. The website design including color scheme and layout must be done as well as the creation of the database tables and the actual code to complete the project. Additionally I would like input and feedback on the design ideas I have. I have created basic drawings of the site as well as a basic database design. I've never worked with anyone at an hourly rate before. I was thinking it would be necessary to create milestones to move the project forward in an organized manner. Let me know if this project interests you. Thanks.