Find the previous semester of the selected month

[pricter]

Hi,
My package is based on cognos cube.
The time dimension has the following structure
Year
Quarter
Month
I want to find the previous semester of the selected month for example
For example if the user select 2012Jan
I want to find a way to have a set of 2011Q3 and 2011Q4
For example if the user select 2011Dec
I want to find a way to have a set of 2011Q1 and 2011Q2


any ideas????

[MFGF]

Are the semesters defined in the cube anywhere? If not, do you have any specific rules for defining how to calculate the start and end of each semester?

MF.

[pricter]

The semester is not defined in the cube
The first semester is from Jan-Jun and the second is the Jul Aug
For the first six months of the year I would like to find the second semester of the previous year
and for the last six months of the year I would like to find the first semester of the current year