Need Help with Triggering Checkboxes to Other Cells

[Jen L]

Excel Help Needed.jpgHello, I created an Expense Report for my company and we want it to have checkboxes for Billable & Indirect at the top, and then when someone checks Billable, in a separate column "Expense Category," only the billable items come up in the dropdown list, and when someone checks Indirect, only the indirect items come up in the dropdown list. I know how to make the dropdown lists; I just need to figure out how to get the checkboxes to trigger to the expense category cells. I'm attaching a picture; hopefully it helps convey what I am trying to explain. I would really appreciate any help with this! Thank you!