DAX date formula question

[joe321]

I have expense reports with employee MTD,QTD and YTD totals. If employee 1 was in Marketing from Jan 1 - Jun 30 and Accounting afterwards, I'd like expenses incurred by the employee to rollup into marketing if expense occurred while in that group. So in the YTD calculation, the total should be allocated to marketing for expenses incurred until 6-30 and accounting for expenses incurred after 6-30.