Ability to build external software packages when building 3DSlicer?

Dear Developers and Users

I have packages that use CMake to compile and install them. I did the steps of building them independently on Ubuntu 20.04 with commands such as cmake and make successfully. Also I built 3DSlicer as mentioned in Build Instructions — 3D Slicer documentation successfully.
At now I want to add these packages to 3DSlicer so that they can be built while doing the building process for 3DSlicer.

Please guide me to doing it.
Best regards.