How can I create a sign-up sheet that deletes choices as the open slots are filled?

Question

I need to create a sign-up sheet on a SP 2007 site for an upcoming conference. During the conference, attendees will be split up into groups to discuss 9 different topics of interest. I need a sign-up sheet that will allow for an attendee to sign up for a particular topic. Once the slots are filled (6 available for each topic) I need that topic to drop off the list of available choices so no one else can sign up for that topic.

I have investigated using a custom list as well as a survey for this, but am struggling with finding a way to eliminate the choices as the groups fill up.

Thanks in advance for any help.

Answer 1

I will use SPD WorkFlows to do the check and removal. You can have a workflow initiate on Item Created and Check if the slots are filled and depending on that value. You can then remove the choice or remove the item from the list. I would create a list that holds the slots and create a lookup column related to that list within the sign up sheet. Once the workflow has noticed that the room is filled it can remove the room from the lookup list which would remove it from the sign up form. Hope this leads you in the right direction.