Hi Iftekar,
I'm guessing at your overall process need and I'd need more detail to accurately answer your query but...
...from the primary item can you use 'related item exists' (work with related items) rule so the related items are effectively at hand to the current user ...and for each item (in the 'loop' of related items inside the rule) use 'assign ownership'? ...then 'release ownership' when finished?
Not tested, ...and not sure how this would work if anyone or any process already has a lock on a related item.
-- Brad.
