@UNKNOWN.DESIGN.LABMy idea is to open each of drawing with blocks which you got from Italian furniture manufacturer and rename blocks in them.
In AutoCAD for Windows you can do this with a few steps with standard RENAME command, using * (wildcard) for equal part of the name of each block. So in RENAME dialog you can select all blocks which name starts with "Gruppo" and change this "Gruppo" prefix to something else just in one click. Once you will rename blocks in such a way each "library" drawing, you will not get troubles when you insert blocks from such drawing.
On Mac the RENAME command doesn't have such functionality. So you need to rename manually one by one or find AutoLISP routine which will do this work for you.
I tried to fins such routine, but they all are for AutoCAD for Windows as they have VL-functions which are not supported on Mac....
But seems I have found workaround:
1/ Create new drawing
2/ Attach the Italian "library" drawing with XATTACH command
3/ Now use -XBIND command with Block option and type * (asterisk) when AutoCAD ask for name of blocks to bind.
Here is sample command line output:
Command: _xattach
Attach Xref "HAMILTON": /Users/max/Documents/tmp/HAMILTON.dwg
"HAMILTON" loaded.
Specify insertion point or [Scale/X/Y/Z/Rotate/PScale/PX/PY/PZ/PRotate]:
Command: -XBIND
Enter symbol type to bind [Block/Dimstyle/LAyer/LType/Style]: b
Enter dependent Block name(s): *
111 Block(s) bound.
4/ Now you have new drawing you created in step #1 with block names prefixed with "DRAWING_NAME$0$" where DRAWING_NAME will be the name of the "library" drawing.
5/ Save this new drawing and use it for inserting blocks to your working file.
You may also rename "library" drawings in order to get shorter prefix in block names.
This is only quick workaround, as I wrote before you can rename blocks in AC for Windows if you ave access to it.