Attendance (plugin)

The groups problem has indeed been fixed in the Attendance module. I was going to suggest the same thing--each station with their own group would work fairly well. Since people can belong to multiple groups, you can also create groups based on level (e.g., Fire Fighter II, Fire Fighter I, Engineer, et al.) and special certifications (e.g., EMT, Paramedic) so you can quickly check who in a specific group still needs the class.