THe first thing is you have to design ur entity in such a way that you can get the values posted.
And you can use :
@Html.ActionLink("SaveChanges", "AddUserToGroup", new { id = item.ID, CollectionName = item.CollectionName,coll = item,model=modelWithCheckedValues }, new { @class = "lnkDetail" })
This is just a eg.
so while posting the data you can get that checkbox values in your post action method.