Page alias names problem

[march_in]

When i'm creating new page and trying to give the same title and menu text as the page i created before i recived:
Alias has already been used on another page
i would like to have structure:
4 Hazetta
4.1 -  Nr 23
4.1.1 -  -  Str 2-3
4.1.2 -  -  Str 4
4.2 -  Nr 21
4.2.1 -  -  Str 2
4.2.2 -  -  Str 3
4.2.3 -  -  Str 4
4.3 -  Nr 20
4.3.1 -  -  Str 2
4.3.2 -  -  Str 3
4.3.3 -  -  Str 4
So page aliases Str 4 are the same.
The solution is- create page with different alias e.g. "blabla" and then rename it to demanded i.e. "Str 4".
QUESTION IS:
Is this solution has any unpredictible for me results?

2 Secon problem is that when i first time name page "blabla" and then rename it to "home" for example then i can't use name "blabla" again. its not possible to reuse that particular name.

[tsw]

alias name must be unique.

on similar cases Ive used some prefix for aliases like

1. something
1.1 something_info
2. else
2.1 else_info
3. more
3.1 more_info

when all of those parents would have page named "info"