I would normally create several hierarchies within the Date dimension, such as Calendar, Financial and others that contain just financial year, calendar year, quarters etc.
If you have another hierarchy that contains the month, you could crossjoin with the year of the hierarchy you are using at the moment; then you won't be using the same hierarchy twice in the crossjoin function.
E.g.
, NON EMPTY {
( [Date Dimension].[Financial].[Financial Year]
* [Date Dimension].[Calendar].[Month] ) }