Two Separate Roles

Hi All, 

I have an employee that has been offered 1 role for 3 days and another role for 2 days. If I add them as a Mult they will not get the correct holiday allocation and wont report into the correct manager. When they do take holiday it will only come from the main role and not the mult. Does anyone have any advice, can I set him up as an employee twice or will that cause issues with HMRC etc?