Hi,
A report is not what decides how many threads you need, it's the issues that you have.
1) CR supports 2d and 3d Charts.
2) If charts are placed on the Group Header and if the each group is set to print on a new page, then this chart will appear on each new page along with the group.
3) I can't really say why the chart you created is not appearing in each group. Please post a new thread with a few screenshots and possibly a report with saved data and I'll be glad to look into it.
-Abhilash