Yes, based on your requirements I would try to use Forge 2 instead. Forge 1 was not really designed to be extended in this way. It's technically *maybe* possible, but I wouldn't really want to try.
Additionally, since Forge 1 is not being changed (just maintained) because Forge 2 is nearly here, I would definitely look at Forge 2. This problem was considered when designing it, and should allow you to do what you need.
Take a look at the `BuildSystem` (BuildSystem does not necessarily build the project. This name may need to be updated to be clearer of it's purpose; it to be ProjectLocator. Perhaps ProjectProvider would be a better name.):