Thanks for your suggestion. Currently, you can assign specific lines on an invoice to a project, which is about as microscopic as you can go at the moment when referring a certain product or sales code to a project. This can be done under Project Settings.
As far as actually automating this process so that any time a sales code is raised it is attached to a project, this is not something that we have considered implementing before as this takes automation to an unprecedented level in KashFlow. Unfortunately this is not on the roadmap at the moment.
I hope that I have understood your suggestion correctly.