Is it possible in Excel to have a font that automatically generates a 'Data Matrix'-Code from a text string. (As it is possible for usual Barcodes) Would I perhaps have to use a Add-In, because the font isn't "linear" or "one-dimensional" as barcodes are?

EDIT: I found a solution (using a pretty expensive software):

I simply used "NiceLabel", which is capable of using XLS-Tables as databases. Then I generated the Codes (Could be Barcodes, QR-Codes, Data Matrix Codes) from the cells in Excel.

This solution doesn't automatically generate a 2D-Code into an Excel-Cell but fits for my personal needs.