Row numbering in RDLC

Hi to all

I have problem with row numbers in rdlc. I need my print layout to be grouped by [field] value. So I've add Row group by [field]. Grouping is ok, but if I count line numbers in C/AL the result in Row number is (for example):

3. Item 2
1. Item 1
4. Item 3
2. Item 4

So to solve this problem, I'm using RowNumber(Nothing) in expression and then I'm getting this result:

1. Item 2
2. Item 1
3. Item 3
4. Item 4

and this seems just fine, but, there is one huge problem there. When I need to print two or more copies from the report, I'm getting this result

Copy 1: | Copy 2:

1. Item 2 | 5. Item 2
2. Item 1 | 6. Item 1
3. Item 3 | 7. Item 3
4. Item 4 | 8. Item 4

and so on.

Does some one have idea how to solve this.

Best regards to all