Add an Element to an ElementRange

Here is a screenshot to illustrate my question:

I have an ElementRange as illustrated by the selection in the screenshot. I need to add the two follow li elements to the ElementRange because they have the same status attribute value ("new"). Give an ElementRange, how do I add the next sibling element to the ElementRange? I am content with adding them one at a time, if necessary. I have some ideas and will post some code, but I am trying to get a head-start by asking here. Thank you very much.