I'm a little confused. Are you getting the license errors from your Production instance? Or your Development instance(s)?
Typically, the DEV and PROD environments would be completely separate so there should be no effect ion your PROD environment when you developers do anything. If your developers are all connecting to a single DB form their individual site instances, and you have web farms enable on your development environment, then you could encounter the issue if you exceed the number of servers allotted, although most localhost licenses do not have a server limit.
Assuming the issue you have is with your DEV envinroment, possible alternatives to your current setup:
Disable web farms for your DEV site. Typically, this isn't an issue as developers are constantly working with different objects and files. The web farm sync will only sync content / data changes, however, this should be able to be managed with using check in/check out and good development practices.
If you are using V9, you could leverage the new Continuous Integration support. It was designed with team development in mind and may be a great way for you to sync changes to each developer.
Have each developer use an separate database and leverage Content Staging to move changes between the instances. This would use a lot of built-in functionality and let your developers work independently.
If your issue isn't like i described above, please give a little more details and we'll try and figure out what the issue is. From what you provided, I am having a hard time visualizing what your environment looks like and made some assumptions my response.