RunTestCase input and return proeprties of the same name

Hello! 

I have a test case module that loads a set of around 100 properties from multiple databases, performs some logic with the data and then outputs the whole set into the testcase properties.

I want to have the option to input some of the properties into the test case when I use a Run Test Case test step and if my logic detects the input, it won't load those specific properties from database. 

What I am struggling with is that if I set the Run test case step properties as Return properties, it ignores the data i put into the Run test case properties, and if I don't set them as return properties, the empty input properties don't get overwritten with the DB loaded data.

Do you have any tips how I could achieve to have shared input and return properties?