You cannot just install two apps directly without showing the user, the thing that you can do is to create a new app in which you will put your 2 apk files in the "raw" folder inside build folder. And push them to open together, those app will show a dialog to user to ask about permissions and will be installed if user allows.
Here is the code to do that:
for (int a=0;a<names.length;a++)
{
InputStream in = null;
OutputStream out = null;
try {
in = getBaseContext().getResources().openRawResource(array[a]); // Here "array" is actually and array holding the reference of apk files (eg. R.raw.firstApp)
out = new FileOutputStream(Environment.getExternalStorageDirectory().getPath()+"/"+names[a]+".apk"); // Here "names" is an array holding the names of your apk files (eg. "firstApp")
Log.e("Path" ,Environment.getExternalStorageDirectory().getPath());
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
in.close();
in = null;
out.flush();
out.close();
out = null;
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory().getPath()+"/"+names[a]+".apk")), "application/vnd.android.package-archive");
startActivity(intent);
}catch(Exception e){
// deal with copying problem
}
}