Question

 Does BarTender support subdivisions/segments on the Data Matrix symbology? 

Answer

 That division in the barcode occurs automatically once it reaches a certain size, and by default the Data Matrix barcode size will increase in the most efficient way depending on the data it contains.

If you instead wish to have those subdivisions no matter the data you enter you could predefine an actual size for the barcode:

If you decide to define a fixed size, be aware that the barcode will then have a "limit" to the amount of information it can encode, as it won't be able to increase it's size past the defined values.