SAP Portal, where is setting defined for which backend system contains Homepage Framework config

Hi, we have one SAP Portal and two SAP backend systems (Finance, and HR). Currently the Portal references the backend Finance system for Homepage Framework configuration settings. We want to move the configuration to the backend HR system. My question is where is the setting that effectively defines which backend system the Portal uses for the Homepage Framework configuration settings. I want to change this setting in our DEV environment, but nobody seems to know where this setting is stored. Kind regards, Jon.