Anshuman, you can do it by script. (This is how I usually do such things, coming from the SQL*Plus era, when no great tools like SQL Developer and alike were around... '95-'96)
Someone already wrote about how to do it by scripts, see this article:
Whether you are using an old version like 1.5.5 or the latest 4.1, despite selecting multiple tables from the Navigator tree, only one object at a time in the object browser can have the focus The action selected from the Actions... drop down list will only apply to that object. You also probably noticed the Navigator tree context menu only displays the Export and Quick DDL items when multiple objects are selected, not those other actions.
Recently a similar question came up on the forum regarding multiple object selection for user-defined XML extensions of the Action type. It may not be relevant to your case, or more than you would wish to pursue, but here is the reference... What is OBJECT_NAME for multiple selection when using xml user-defined actions ?