Combine <use>-tags or make <path> out of <use>-tags

Using SVG via Inkscape:

I have several <use>-tags, which are reusing the same <line> (from the defs), while transforming it.

Now I want to create a shape (<path>) by combining some "transformed lines" and connecting the end-points. Inkscape has a tool to combine paths, but it seems to me that is not possible to combine several use-tags.

How can I create a separate path from a <use>-tag, to later combine them into one path?

simplified example:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
    <defs>
        <symbol id="extended_segment">
            <line style="stroke:#000000;" y2="240" x2="615" y1="240" x1="240"/>
        </symbol>
    </defs>
    <use xlink:href="#extended_segment" transform="matrix(0,-1,1,0,330,615)" />
    <use xlink:href="#extended_segment" transform="matrix(0.5,-0.8660254,0.8660254,0.5,242.1539,462.8461)" />
</svg>

This example should result in a triangle-shaped path…

Solution

Finally found it: It's unlinking clones, which will create new path/line-elements.

If necessary, a clone is easy to convert to a regular object – that is, to cut its link to the original. For this, go to Edit > Unlink Clone or press Alt+Shift+D when the clone is selected.

Here is the source