To have full control of pen mapping, always use the Keep Pen Index Number translator, and customize it for your needs.
As for combining sheets the way you want it, I'm not sure, but Archicad's Help menu has quite comprehensive explanations about the available options for DWG translation.
Open the External Content > DXF-DWG Translation Setup dialog, and right-click to get the Help option. Select it. Checkout the Save options.
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1