Loop Recursive in jobs.

Hi

I have something like this in Job Table.

Extra Field named : ParentNumber

Data could be like this

No ParentNumber
1000
1010 1000
1020 1000
1030 1000
2000
2010 2000
2020 2000
3000
3010 3000
3020 3000
3030 3000
3040 3000
7020 1030
7030 1030
7040 1030

There can be several levels ( 5, 6, 7 .....)

I need to put the result into a Temp Job table.

The BOM Compont STRUCTURE page have something like, but have tried do figure out how it do it, with no luck
I have done something like this in SQL, and C#.. But can't figure this out

Someone that can give me a idea, how to get started.

THANKS