Any ways to combine Android APK with Expansion pack file?

I want to have only one APK that contains all files and resources without having to download expansion pack every time.
Is there any way to combine Android APK with Expansion pack file?
My expansion pack format is main.build-version.package-name
The reason I want to do this is because decompiler fails to find some resource files and the apk has expansion pack which adds some files after its installation so I need to have all resources and files in one place.