You should export those blocks from source drawing using WBLOCK command for further access - save them on disk as separate files.
If the target drawings already exist, then create a list with their names using a BAT file and this code:
Next step will be to create the script - I suggest you to use Excel for that. Don't forget to save it as plain text using SCR extension.Code:DIR /b *.DWG > drawings.txt
If the paths of blocks to be inserted and/or target drawings contains spaces, should surround them by quotation marks.