Hi,
When you say the IT Costs by owner table what are you referring to? Which specific report? You can add slicers to reports but this will be a customization and in turn can hinder your upgrade path. Instead, you could just type in the name of the owner in the owner coloumn to see their aggregate spend?
Apptio has an OOTB report showing you the IT owner costs in the IT Management, Finance tab. It already summarizes the cost by owner here.
Let me know and I can help further.
Thanks,
Lauren Griessel