Here's a query you could use to identify them:
select oh_name as workflow,
jpp1.jpp_object as task,
jpp2.jpp_object as successor_task,
jppa_when as successor_dependency
from oh,jpp as jpp1, jpp as jpp2, jppa
where oh_idnr=jpp1.jpp_oh_idnr
and oh_idnr=jpp2.jpp_oh_idnr
and oh_idnr=jppa_oh_idnr
and jpp2.jpp_lnr=jppa_jpp_lnr
and jpp1.jpp_lnr=jppa_prelnr
and jpp1.jpp_object='[[ task you want to find the successors for ]]'
and oh_name='[[ workflow where this task is found ]]'
and oh_client=[[ client
You could bury that in a SEC_SQLI var, for example.
Again, how are you intending to use this info about successors? Just wondering if there might be another way to approach the problem...