The Windows group for developers sounds like a good idea and Vidhya's suggestion of using the SQLAgent roles in msdb is a good choice for allowing non-sysadmins to maintain jobs. You should review the permissions for the role in BOL to make sure it's what you want.

If you want to restrict database access to smaller groups, you may want to create Windows groups for each of those and make them members of the larger group. In our shop, we have multiple systems and each system has it's own group of developers.