If you have already created the report in design view, switch to layout view on the view tab, just below to the office button. Then in the tools bar and on the "Grouping & Totals" region, click "Group &Sort".On the bottom of your report, click the arrow on the "Group on select field".
In the drop down, click on one of the fields you would like to base your grouping on, Client Id or Name Preferable.In the same region,click on the arrow on "More", then finally near the "less " arrow, The drop down arrow has an option when clicked "Keep whole group together on one page" .Select it. You can then switch back to print preview mode to see if it works.