need to copy comments from child linked issue to parent linked issued ( when child issue is closed)

[siva]

we have added post-function to create a linked ticket when transition is done from A to B.

once a linked ticket is created ( linkA ) , and if the linked ticket (linkA) is transitioned to closed.

i need the comments from closed linked ticket ( linka) to be copied to the parent link issue.

we user JSU and BOB-SWIFT plugins.