Hi Simone,
Usual method to run one Package after another ends is Package Link, but it looks like in your case you need any Package after some certain Package. If that is not true just use Package Link.
In case you need a number of Packages dependent on a single Package it depends what is in those Packages. If you have some custom code in them then you can check Dimension table - it has status of Dimension and you can see if it's being Processed or not.
Another option is if those Packages are scheduled. Then you can use SAP standard tools for events.
So, basically for each particular case you can find some option:).
Regards,
Gersh