I have not tried to accomplish this requirement using DevTest so treat everything below as an unproven idea that may or may not work.
Option 1:
1) Create a test case step that reads the first dataset and stores the information (Key/Value) in a List object
2) Create a second step that reads the second dataset and stores the information in a different List object
3) Add a JSR-223 step that compares the two lists and provides the necessary response
Option 2:
Look for a method in the DevTest framework that can help you. For example, testExec.getLocalDataSet("dsNameHere") might give you a handle to each of the dataset objects. Perhaps, your code could access a method to return a list of key values or an XML representation that you could perform an assertion on. You would need to review the class hierarchy to determine if this approach is feasible or not.
Option 3:
Read the first dataset in a test case, create a for loop that calls a subprocess. Pass each only the column name and value to the subprocess. In the subprocess, access the second dataset and compare column name and value. Return the result of the comparison.
You may bump into an issue when referencing a column name [i.e., testExec.getStateValue("colNameA") ] since it appears that both datasets share exactly the same column name. In the above, there is no distinction on the property name called colNameA as to which dataset it belongs. Hence the reference in Option 1 to processing the dataset into a list that can be referenced later.