This works by finding the matching email address, returning their employee ID and then using the ITEM() function to find the relevant Dimension to return, rather than a text value.
I tried it but I have this error message : Error: Dimension error: formula Dimensions and current Block Dimensions are not compatible. Can't implicitly remove Employees Dimension(s) on non numerical Metric.
This works by finding the matching email address, returning their employee ID and then using the ITEM() function to find the relevant Dimension to return, rather than a text value.