How do I setup Jenkins to handle multiple projects that depends on each other..?

[Kenneth Nielsen]

we have a tree like structure to our projects.

myexe

+- mylib

 - myunittests

 

How do I set it up so jenkins will only build myexe, when it og my lib is changed?

 

And build mylib and run myunittest when it i changed.

 

And is there a smart way of keeping the changed mylib and unit test for referncing in myexe. When running under Jenkins?

 

Thanks

Kenneth