Question

I have template for every project that I use is a button block that generate everything for a new project. Inside it, it has more button block templates. In some projects, I realize that I need to add more things to my base template. The problem is, that I add this new thing to my template and to the current project. But I can't do that on all old projects. And those are projects that are currently active. With sync blocks, I think, I can't doit. Because the template has several templates inside them and because is sync two direction. That is, if I change on a project it will change on the template and I don't want that. I thought to have a sync template and the instance of the project, but I just have to pass all the information and is not a good solution at all.
Do you know how I can fix this?