Import Assemblies into an Assembly

I have a large assembly that I’d like to import into a second, large assembly into to create a very large assembly.

I’ve been using the A2+ WB for creating assemblies and have been using the so-caled forked version of FreeCAD (Realthunder). Here, I define an assembly as an aggregate of parts that, by using Attachments and offsets, an assembly is constructed from individually created part files.

I’ve found that importing an assembly into another assembly using the A2+ WB causes pain. For example, colors are lost, the imported assembly becomes a single color as if the WB treats the imported file as a single part. Is there a preferred WB (Assy3 or 4) that specifically enables the import of assembles? I’m looking for a “button” that says “Add assembly” but nothing found.

TIA!

I use Assembly4 for this purpose. It handles multiple nested sub-assemblies quite well. There is an “Insert Part” tool which recognizes sub-assemblies saved in separate files. See instructions here: https://github.com/Zolko-123/FreeCAD_Assembly4/blob/master/INSTRUCTIONS.md

For expert guidance on Assembly3 see jpg87’s excellent website: https://help-freecad-jpg87.fr/02_ass_ind.php