Microsoft Excel - Colors - Alternative Row Colors

Select the entire column with the group numbers.

• Select the data range.
• In the Home ribbon select Conditional Formatting → New Rule.
• Choose Use a formula to determine which cells to format.
• In the formula cell, put =MOD($A1, 2)=1 as the formula.
• Click Format, select the Fill tab.
• Select the Background Color you want, then click OK.
• Click OK.