Starting Quarter In Options

Simple I know, but I run a business who's financial year starts on August 1st and therefore Q1 (Jan-Mar), Q2 (Apr-Jun) is out of kilter with us. We maintain a database table with dates that match up to our quarters and as we connect to Access for a lot of our data, it sort of overcomes it, but with more context sensitive filtering in Pivot Tables, Tables, etc it would be nice to have an application and workbook setting to set the start of Q1 (e.g. August) and then have Excel use that for all or just the current Workbook for all it's quarter filtering

To take it one step further I would like to be able to define the time heirarchy based on a calendar that I define. You can upload custom lists so why not custom calendars. We run 4/4/5 periods to make up 13 week quarters. If I could pivot that directly life would be grand...