Datagrid - toggle line selection by clicking

[Glen Bojsza]

In the world of consistency, I have the need to use a combination of
scrolling fields and only a couple of datagrids.

So for the user experience I would like them to be able to select and
deselect (toggle) multi non contiguous lines similar to that of a scrolling
field... currently in OS X you would hold down the command key to toggle in
a datagrid.

Any suggestions on doing this (I have not really used datagrids and
therefore cannot appreciate their full in's and out's)

thanks,

Glen