How to update massively the values ​​list of the fields of the Descriptive Flexfield?

Content

Hello Guys,
I need to upload a values list of a field of a Descriptive Flexfield: Organization Attributes.
This Flexfield is on the Organization and it just has got some values, I want to load massively other values.

Is it possible to do by using .dat file?

I hope in your help

Best regards,
Giuseppe