Can you open .blend files in .blend files?

More like importing I suppose. Donno, anyways, anyway to open .blend files while working on a .blend file, so that both .blends are in the same blender and can be modified etc. together? Thanks.

File >> Append and you can bring the whole scene into the .blend you have open.
Ctrl-L and you can link to a scene

Or open two .blends and drag the windows so they’re side by side on your screen.

%<

thanks ^^