http://creators.xna.com/en-US/education/bestpractices31 XNA Creators Club Best Practices for Indie Games - Your class project requirements force this.
Textbooks that introduce XNA 3.0 Game Studio and I would like to sponsor a short tour of those available from our SDSU Library as one of the Safari Textbooks which you can access with your Library Pin.
proquest.safaribooksonline.com.libproxy.sdsu.edu/ Search for XNA there are 2 pages for XNA 4
昄oading 3D Models from files; scaling, rotating, moving, and drawing them into your 3D world (recipes 4-1, 4-2, and 4-6) 昉olishing the movement of your Models by making sure they are always facing the direction they're going to and by adding acceleration (recipes 4-3 and 4-4) 昄etting the user select Models using the pointer on the screen (recipe 4-19) 昅aking your Models come alive by visualizing their structure and animating them (recipes 4-8 and 4-9) 旵hecking for collisions between your Models by using some fast mechanisms (recipes 4-10 and 4-11) 昄earning how you can detect collisions on the finest level of detail, by checking for collisions for each triangle of your Model (recipe 4-18) 昍endering your Model using your own HLSL effects because the BasicEffect class no longer suits your needs (recipes 4-7 and 4-12) 旹xtending the Model processor so you can access much more useful data in your XNA project (recipes 4-13, 4-14, 4-15, and 4-16) 昄earning how you can store objects of your custom class inside a Model when it is loaded and processed in your custom Model processor, by coding your own TypeWriter and TypeReader (recipes 4-15 and 4-16) 昅aking your Models nicely follow the slopes of your terrain (recipe 4-17)Author web site for code
Tunnel Vision game images from Chapter 23
Each of these textbooks will have a slightly different way of developing the 3D capabilities you expect to use for your 3D group game.
FYI - the textbook used last semester has been updated for XNA 3.0, but it is not available for free from Safari Texts. http://apress.com/book/view/9781430218173 Beginning XNA 3.0 Game Programming: From Novice to Professional by Alexandra Santos Labao, Bruno Evangelista, Jose Antonio Leal de Farias and Riemer Grootjans.
Another resource is XNA Creators Club