Right-click the second section and from the context menu, click Conditional Formulas.
Select Suppress and then click OK.
Enter the following formula:
Remainder (RecordNumber,5) <> 0
This formula divides each record number by 5. If the division produces a remainder, it suppresses the blank section. But if the division produces no remainder (which it will for every fifth record printed), the program prints the second section, thus inserting a blank line.
Note: To insert a blank line under different conditions, you can modify your formula appropriately.