I recommend you get them all thinking towards the same goal. Creating user personas are a great way to do this.

Personas allow you to roughly summarize the kinds of people interacting with your site. When you have a “specific” person in mind, it’s easy to build the result successfully.

An example persona might be: “Susan is a middle aged mother with an interest in pottery. She doesn’t spend much time on the computer. Her main experience with the internet is buying books and supplies.”

Using the Susan persona, how would you create a site she would be comfortable in? What elements matter most?

Brad Colbow drew a nice comic about personas recently that explains the concept in simpler terms.