In merge mode, allow the selection of the HTML element to include instead of the whole page

Problem/Motivation

Sometimes one don't need the entire external site page to be integrated but rather just a part of it.

Proposed resolution

Add a filter mode that, instead of removing or replacing an element, it would include it (with possible alterations). Only included elements would be integrated and the rest would be wasted.

If you feel like it would a good feature, please subscribe to this issue or add a comment to help me evaluate needs and priorities.