Changing the value of datagridComboBoxColumn on checking/unchecking of check boxes in datagridcheckbox column in a wpf datagrid

Question

I have a wpf data grid,where there are two data template columns One of which ahs check box as the data template adn teh other has combo box as the data template.

Now my requirement is,i need to disable few of the options in the combo boxes depending on the check box checked or unchecked for each individual rows...

With the cod etaht i ahve tried,i am able to change teh values of teh combo boxes,but it changes for the whole column and not fro individual rows..

Please let me kneo how to determine the combo boxes for the corresponding check boxes in a particular row.