Select Code to Download

Issue in detail:
Let say we have 4 major tasks: A, B, C, D such that following combinat
+ions are considered valid:
...
4) A->D
 and so on.
Note: same was mentioned above earlier.

<!--Make an xml file something like below-->
<xmlFile>
...
        </postTasks>
    </action>
</xmlFile>

Object Oriented approach.
1) make code file which has such customized details. (derived class)
2) provide override mechanism to end user. 
3) support flow of tasks like mentioned in xml but remove perl code fr
+om there. There are several alternatives to do this which maybe as si
+mple as reading properties file.