Hi,
Sorry for not being able to answer and yet responding to your question.
Just wanted to say that -> Happy to note that people are still using SIS 
Been a while since I used it. You could check in the characteristics if this is available. I am sure you must be aware that - Characteristics and Key Figures are used in configuring the Info Structures.
I don't think it will be in Update Rules which are basically for when the update should happen and not what the update should be.
Thanks.