How to create a dependency of a fat jar

I have a fat jar with other jar’s included. The content of the fat jar is like:

0 Thu Aug 17 15:28:16 CEST 2017 META-INF/
77 Thu Aug 17 15:28:16 CEST 2017 META-INF/MANIFEST.MF
 0 Thu Aug 17 15:28:16 CEST 2017 lib/
61685 Fri Oct 21 18:08:30 CEST 2016 lib/lib1.jar
66552 Fri Oct 21 18:13:30 CEST 2016 lib/lib2.jar
92666 Fri Oct 21 18:08:20 CEST 2016 lib/lib3.jar

how i have to write the dependency of this jar, so that the included jars are also dependencies.
for example:

dependencies {
    runtime files('mylib/myFat.jar')
}

doesnt work.

Thanks.