Suppose A is parent type and B is child type. They are linked by some token. A has its ID by that token.
Now B has a field 'event'.
At time t1, B type doc was indexed with 'event' = success against some parent 'A1'. Now at time t2 another doc was indexed with 'event' = fail against same parent 'A1'.
What I have to do is find all parents which never had any child or had only 'event'=success child (not a single 'event'=fail child). Is this possible?