I don't have any suggestions for you - but I wonder if you can share how you tackled this? Did you figure out a solution for your above problem?

For collecting the id's did you just do like:

var output;
var array = editorGrid.getSelectionModel().selections.items;
for(i=0;i<array.length;i++){
output += arrayi.data.someId +',';
}

or is there a simpler way?