How about using a helper column and concatenate column B with I and then format the helper column.

Example, I used column J as the helper column...

Conditional Formatting
  • Highlight applicable range >> J2:J20
  • Home Tab >> Styles >> Conditional Formatting
  • New Rule >> Use a formula to determine which cells to format
  • Edit the Rule Description: Format values where this formula is true: =COUNTIF($J$2:$J$20,J2)>1
  • Format… [Number, Font, Border, Fill]
  • OK >> OK

If this does not do it for you, then how about a sample workbook with a before and after.