So this issue plagued me for awhile but I just recently found the answer in a support forum at MacWorld.  Our school has multiple airport extremes that make up our wireless network in the main classroom building as well as the resident halls.  The airport extremes allowed timed access (or no access) to the internet by configuring the Access Control section under the Airport Management Utility.  The issue I had was that you had to add and configure them one at a time.  After reading this article, I found that you could import an Access Control List that made adding multiple MAC addresses a breeze.

First you need to create your Access List.  Open up TextEdit and create a text file of MAC addresses and device names.

i.e. 00:11:22:33:44:55 JRobinson
99:88:77:66:55:44 RSmith

Once you have your list done, save it in Unicode format and open up the Airport Utility.

Click on File on the menu bar and then hold down the Option key.  You will notice the Import Configuration File changes to Import Access Controls.

Select that and choose the file you just created with your Access List.