Custom toolbox - Key-in command for multiple raster attach

Hello.

I'm creating a custom toolbox in a .dgnlib file that allows me to attach raster with a single click. To attach a single raster I use the command:

raster attach fixed "<filepath\filename>"

Is there anyway I can create a button that allows me to attach multiple raster images?

Regards,

Bjorn Magnus Arnason

Stod ehf.