How to specify Index to use for CAPM Beta calc

I can see examples-simulated is using the SPX in its CAPM Beta calculations. It is also defined in the dummy simulation file market-data.csv. But I can’t figure out how this is defined in OG configurations, as I want to change to use another Index. Please how is this normally configued? Thanks

Please any ideas on this? Thanks.

Please can you confirm if now configurable? Thanks