internal link in menu, auto jump to submenu

[lukas123]

I have menu structure like this:
1 - 1.1 1.2 1.3 1.4
2 - 2.1 2.2 2.3
3 - 3.1
4 - 4.1 4.2

I need 2 things:
INTERNAL LINK IN MENU
- for example when 1.4 is clicked  go to 3.1
- what should I set in URL and CONTENT TYPE for 1.4 (i don't want use absolute paths - they can change)

AUTO JUMP TO SUBMENU
- when 1 is clicked go to 1.1, when 2 is clicked go to 2.1,....
- when 2.1 is clicked go to 2.1.1, and so on