Parallel Period filter (MDX) -

i want add working days inside parallelperiod function below, there way filter or except (like working days, count until yesterday)?. code below info gets measure x previous year ytd

 sum(    ytd(    parallelperiod(    [Χρονική Περίοδος].[year quarter month].[year name],    1,    [Χρονική Περίοδος].[year quarter month].[year name].&[calendar 2015])    ),    [measures].[x]    )