Date validation in Infopath 2007

In SharePoint infopath forms I need to implement one thing which was a bit tricky as it is not the default supported by infopath forms. The requirement is like this: The date fields on form should not allow date plus/minus 5 years from current server date. For this, so many people recommended to implement validation events in c#. But, my form contains 40+ date fields. That is not possible to implement events for each control. But, when I looked into all option there is an option called “Data Validation”. But, there is no direct option available to implement this requirement.......