One way to make this easy is to build templates, distributed to all developers, which incorporate the most frequently used connections, with config files created for each.

the advantage of this is that, one config file could be used by numerous SSIS packages, and one SSIS package can be run numerous times, each one with a different config file.

The setup I have one the servers is one folder for the generic config files, and one folder for package specific files.

This makes config file management simple.