For the AX 2012 R2/R3, there is a field in the staging table called ReleaseProductCompany.
This field is used to release the product to multiple companies; it will do the same as manually release the product.
On the Source data format you can specify a Multi value separator. Using this character you can specify multiple company values.
You need to add a column into your import file for the”ReleaseProductCompany” field and define what additional
companies you want the product to be released on during the DIXF product import.
Responsible code is in \Classes\DMFProductEntityClass\insertUpdate