Calling a package from one solution to another (external package calling)

Hi all,

By default we have the master package that executes a project reference which we call the control package. We pass some varibales and it runs.

For one of our cases now, we have a solution, where we execute a package to call another solution. This is not a project reference type, but an external reference type. However, this seems not possible.

Anyone has experience with this?