Loading values of an attribute to an attribute

Currently, I am loading master data that doesn't contain 0COUNTRY. I want to fill the 0COUNTRY attribute value with the value that is contained in a different infoobject. So, in the update rules I have referenced the attribute of the other infoobject.

However, when I execute the load, the value of 0COUNTRY doesn't show. Any advice? In the update rules does the application not know which value to load?

For example my scenario is as follows:

IO1 - master data that contains IO2 as an attribute

IO2 - master data that contains IO1 as an attribute

when loading IO2 I want to fill the 0COUNTRY value with the corresponding IO1 0COUNTRY. FYI, the value of IO1 as an attribute to IO2 is being loaded simultaneously.

Thanks,

Dave