Required Dependent Data Validation drop down

Hi Friends,

I trying to put a dependent data validation in below attached excel sheet. I have two sheet Dashboard and Data. In Sheet Data i have month wise candidate details and in sheet Dashboard i am trying to put dependent data validation.

Now what i want is, if i select any associate from the drop down menu that time in month drop down it should show the related months of an individual

For Eg: If i select Satish Devadiga in "Associate" Drop down menu, that time in dependent drop down "Month" it should show the months he worked for.

Hope you got my point

Regards,
HD