tree menu with toplevelmenu entries which link to first sublevelpage

hi,

example menu

• ABC
  • A-D
    • A
    • B
    • C
    • D
  • E-H
    • E
    • F
    • G
    • H

the only way i found to create a tree menu where the toplevel entries link to the first subpage was to create the toplevel menu entries manually, which is extremly costly. and there is also a problem with pathauto.

what i want:
"A-D" should link to www.example.com/ABC/A-D/A
"G" should link to www.example.com/ABC/E-H/G
"ABC" should link to www.example.com/ABC/A-D/A
"A" should link to www.example.com/ABC/A-D/A
"E" should link to www.example.com/ABC/E-H/E

what i get:
"A-D" links to www.example.com/ABC
"G" links to www.example.com/ABC/E-H/G
"ABC" links to www.example.com/ABC
"A" links to www.example.com/ABC
"E" links to www.example.com/ABC/E-H

i hope its clear whats the problem, it seems like pathauto takes the shortest way to the link
maybe there is also a better way to define menu entries which link to the first submenu entrie, but i dont found it.
how to make this best?