Hey I got a report that is grouped into 4 groups. I want to number each detail in each group like the following:

Group 1
1
2
3
4
5....
Group 2
1
2
3
4
5.....
Group 3
1
2
3
4
5.....
Group 4
1
2
3
4
5.....

What do I need to do to accomplish this?

Thanks!