Hi Dave,
I do have a suggestion which might not be ideal, but it is worth checking. Instead of creating all tree structure at once, first create "parent 1". Then put the permissions you want on it. Then go on and create all subpages under it at one. By doing so, the subpages willl inherit the permissions that you have set to "parent 1".
That is how I personally do it. Not perfect but still reasonable, I think.
Cheers,
Aderson