Delete SELECTED groups of emails on my touch, not "Delete All" ?

I've searched forums for a solution on how to delete large groups of excess mail in the in box on my iTouch.

Delete-All is not a solution because I need to keep a small selection of messages but dump two or three hundred others from the in box.

Doing it with the Edit feature require one-at-a-time endless back-and-forth clicking. Doing it by mass deletions eliminates everything including those items I want to retain.

Why is it not possible to select large groups (click and drag) and selectively retain individual messages?

The highlighting of all followed by selective toggling of individual items in the highlighted group is a basic Mac function. Why is it absent from the iTouch and the iPad?

Is there a workaround to accomplish large deletions that had selected non-highlighted items that are retained?

Many thanks

---GG