Massive Delete (2 Joins Required) With No Partitioning

I'm experiencing some infinite loop for my delete. I tried many way to deal with this problem but still take too much time. I will try to be clear as possible.

I have 4 implicated table in this problem.

The deletion is done depending of the pool_id given

Table 1 contain the pool_id
Table 2 the ticket_id foreign join ticket_pool_id with the pool_id
Table 3 ticket_child_id foreign join ticket_id with the ticket_id
Table 4 ticket_grand_child_id foreign ticket_child_id join with the ticket_child_id

Concerned count for each
table 1---->1
table 2---->1 200 000
table 3---->6 300 000
table 4---->6 300 000

So in fact it`s 6.3M+6.3M+1.2M+1 row to be deleted

Here`s the constraint :
-No partintionning
-Oracle version 9
-Online all the time so no downtime neither CTAS
-We cannot use cascade constraint
-The normalization is very important

Here`s what I tried:
-Bulk delete
-Delete with statement (In and Exists clause)
-temp table for each level and 1 level join
-procedure and commit each 20k

None of those worked in a decent time frame like less then one hour. The fact that we cannot base a delete on one of the column value is not working. Is there a way I'm getting desperate now