I am trying to set a category folder as a default master category.

I have been using easy populate and have noticed that my master category is set, almost randomly.

I have many categories for example
Baby
Toddler
Etc.

I also have a hidden/disabled category folder which sorts all products by manufacturers. This way when i have a sale i can apply it to one manufacturers items only.

I would like to find out how to set the manufacturers folder as the default master category for any current / additional items added.

Is this possible or do i need to go into each product description one by one and make sure the master category is correct?

Thanks,