Duplication problem

Good Morning

I am going to try and explain this as best i can.

In column A i have a heading of a city E.G london. under this i have a list of people who are working there, under that i have another heading with another city E.G Paris with more people under it. In total i have about 7 cities. Then running through column B,C and D are job roll information and then E1,E2 onward's are marked with day and date of the month with then creates a grid for me to populate with peoples moments on certain days.

I then mark each day a person in that city with a D .

My problem is people on this list will work in different cities though out the month. I am looking for a way to be able to duplicate names in column A but then if i place the same person on shift on the same day in 2 different cities it would give me a warning or highlight the column red.

I should point out that i use 1 workbook per month.

is this possible on excel? sorry if this is in the wrong sub forum

You can see in the upload that some people are working on the same day in different cities.

If anyone can help it would be greatly appreciated.

Attach a sample workbook (not a picture or pasted copy). Make sure there is just enough data to demonstrate your need. Include a BEFORE sheet and an AFTER sheet in the workbook if needed to show the process you're trying to complete or automate. Make sure your desired results are shown, mock them up manually if necessary.

Remember to desensitize the data.

Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.