Quarterly Average over Weekly Average

[gra_wang]

I'm trying to create a line and clustered chart where the clusters/bars show weekly averages while the lines show quarterly averages.

Here is the measure I used to try to get a quarterly average:

Quarterly Average Talk Time =
AVERAGEX(
    SUMMARIZE(subAgentCall,subAgentCall[Quarter],subAgentCall[skill_name],subAgentCall[Call Type],"Average Talk Time",
    (SUM(subAgentCall[SUM TT])/SUM(subAgentCall[Calls Handled]))/60),[Average Talk Time])

Problem is (as indicated by the picture above), all that happens is the line matches the weekly average. Is it possible to create a measure that calculates strictly at the quarterly level and utilize it on a graph using weekly intervals?