Combining modules using "call to test"

I am trying to call to a test that already has a call to a test embedded in it. This is the results returned: 

The call to testSXWEB-T18 does not display the steps required to navigate to the main screen.

Is it not possible to make a call to a test that already makes a call to a test? You can't combine modular tests into a single flow and then use that single flow to create additional modules?

ex: test 4:  >>call to test 1>>call to test 2>>call to test 3

      test 5:  >>call to test 4>>step 5>>step 6     instead of: call to test 1>>call to test 2>>call to test 3>>call to test 4>>step 5>>step 6