Setting up a xojo framework

When I develop an app I often reuse classes from older Xojo projects en then improving on those.
Is there a way to setup a common framework shared by multiple Xojo-projects.
That way I could improve on my framework and get the improved functionality in the older projects to.

What would be the right way to set something like this up.
Importing just creates extra copies so that doesn’t rely work in the long run

Look into the manual section about External Items