Avg Age by FY if BusGroup=HQPEO

Hi. All I need is to get Avg. Age for Business Group HQ/PEO by fiscal year (FY).

I tried a couple of different approaches:
1)
average([AGE] for [FY],[BUSINESS_GROUP_NAME]='HQ/PEO')

2)
CASE [BUSINESS_GROUP_NAME] WHEN 'HQ/PEO' THEN
(
total(([EMPLOYEE...