Hire Someone to make a Imposition script

Im looking to impose business card sized files 12 up onto a larger sheet.  The original files will come in a multipage PDF of up to 750 pages.

The trick is that I need to place the files in specific spots on the page, and when that page fills up, to continue onto a new page and repeat until all the files are placed.  I have a template file with frames where the cards are to go i that helps.

Ive looked at other scripts, but am not versed enough to do this on my own and was hoping someone out there can help.

thx.