Bennett,

You can make a project private and visible only to its members by following "Admin" and then "Edit Observer" under "Group Members."

Luis makes some good points about doing this in general. In addition, NITRC is primarily a site for sharing and discovery (as opposed to a site for supporting development), so we don't normally suggest making projects private. Classifying your project in the tool tree with an appropriate development status (planning, pre-alpha, or alpha) and perhaps making a note in the project summary statement should indicate to users that your tool isn't ready for production use while letting you benefit from the exposure and community interaction for which NITRC was designed.

Best,
Christian