Hello Mishel
I have solved your problem few time ago and have shown it here, but don't remember the thread number.
If you wish, I can send you solution, sure with my testing table
All you need to change in it, to set line numbers available at report at one page without stretching fields.
The solution involve smart group based on the function, which looks on the next record, will it be fitted at page or will be too long.
Best wishes, Vladimir