Silverlight Datagrid column EventTrigger

Question

I have a datagrid with multiple columns. I want to use Interaction.Triggers as a means to fire off a particular method on the view model when only one particular column on the grid changes. How do I find the list of available events for that particular column. I tried using Exp. Blend 4 but I could only see events for the entire datagrid. Also when for that Datagrid event I entered a method name in Ex. Blend 4, it put the code in xaml.cs file. What I want to do is put a tag like so in the xaml...

                    <i:Interaction.Triggers>
                        <i:EventTrigger EventName="{What event to put here}">

                        </i:EventTrigger>
                    </i:Interaction.Triggers>

and write code against that event in the viewmodel.cs file. Any pointers on how to see the list of events for a particular datagrid column in Expression blend.. or any other way?

Also, does this [i:EventTrigger EventName=...] tag have to be nestled within the [sdk:DataGridTextColumn] [/sdk:DataGridTextColumn] tag for that particular column in question or do I need to put it within the datagrid [sdk:DataGrid][/sdk:DataGrid] tag itself. An example demonstrating the same would be nice :)

Environment: Silverlight 4 using Expression Blend 4 & VS2010

Thanks for your time.