Get all the lessons learned into a repository or wiki that all development team members can reference and ideally add to. This does not have to be a complex software solution. Post text files which are named well. Inputs should be flowing into this repository or wiki following every iteration retrospective. It is okay if the structure emerges.
This is especially important if you use temporary project teams like Hollywood that disband after the project to form new teams for new projects. This provides a way to institutionalize lessons learned for follow-on workers.
Another way that is not document-centric is to have periodic sharing sessions between teams. For example if running three projects simultaneously, have the instructional/LX designers meet together for an hour and talk about what works and what has not worked so well. Do the same thing with media staff and software developers on simulation projects.
Some people prefer the written form of lessons learned. Others prefer the social interaction. Pick what works best for your circumstances and people.
Also update your templates for various deliverables with lessons learned from each project, each iteration and each customer stakeholder interaction.