@Tom There used to be a nice extension for that which covered lots of extensions (not just K2). It was called obGrabber (extensions.joomla.org/extension/obgrabber/). Unfortunately that company vanished overnight after many years in the Joomla community, along with their extension. You can try and look for an old copy, you never know...

Actually, someone picked it up.

Have a look here: extensions.joomla.org/extension/authoring-a-content/content-construction/joomgrabber/