Field and Form Rules: External data

Field and Form Rules: External data

Hi,

Is it possible to populate a drop-down menu with values from external sources (say Active Directory) using Field and Form Rules?

An example could be a drop-down menu of all the company sites. And instead of having a static list in the custom field in SD, that needs to be manually updated every now and then, one could simple import the values from the AD Sites.

/Rasmus