I suggest you remodel your data into three (3) tables: Opportunities; Staff; Staff Opportunity Role. Using your data, the tables would be modeled as:
Emp_ID, Staff Name
[Staff Opportunity Role]:
Please note: Due to the way the data would be loaded, John is duplicated in the bridge table as Lead. However, this will not make any difference to totals assuming you are only using the [Staff Opportunity Role] table as strictly a bridge table. But if this is an issue, the [Staff Opportunity Role] table can be easily de-duplicated during load time.