One MCG mapping to multiple Expense Type?

Hi Team, 

For the corporate card mappings, is it possible to have one merchant category group assigned to 2 or more expense type? We have scenarios where in within Travel we have 4-5 Expense types and we are not sure what should be defaulted? So we are asking if we should map 1 merchant category group to all 5 expense types or dont map it whatsoever so that by default when the transaction is loaded on the expense report, the expense type is blank and has to be selected by the employee?