It is possible to mass update using LSMW object with txn code PA40.
a)In PA40 selection screen, create transaction recording for termination action, similar to the one created for hiring. - by entering a personnel.number, from date, and selecting suitable action type. It may be better to skip the delimiting infotypes and create another recording for PA30 txn, as this would have a variable number of records.
b)It is best to create a new LSMW object
(It is possible to copy from LSMW object used for hiring; but there could be too many changes required for the termination object).
c)Go through all the steps in the LSMW txn.
You'd know the details, as you have created for hiring in mass
It is also possible to use Winshuttle or Data Sync Manager (from Epiuse)