How to group this square/rectangle with text in .dxf?

[alucard001]

Hi all

I am currently working on a project which I need to group the separated path and text into one, so that,
when I export it to a SVG file I can see the relationship with the box and the text and do further processing.

As you can see, the black square contains the text (3-C18), but in Inkscape they are totally unrelated/ungrouped.

And now I want to connect this black box and text programmatically.

How am I going to use this library to achieve this objective?

Thank you very much in advance for your help.