Increasing the width of a Header breaks header alignment in multiheader implementation.

Hi

I have already looked up these examples.But I want a Multirow header in which each header can be divided upto any level
Like consider an Employee table whose header looks like :

Employee | Department | Region
First Name | MiddleName | lastName | Inventory | Finance | MiddleEast

I can create the table by providing the Header spans but this grid breaks when user tried to adjust the width of a column by dragging the header.The multiple header width are not able to align properly.Therefore , user will see Finance under Region which is wrong.
I want to keep the slider to the last header.
Can any one suggest me how can I fix the above issue.

Thanks
Vikramaditya Garg