Making Hub position Master in DUW and adding SAU in DUW

Dear Experts,

I am seeking your help to add Hub position ( EC Bus Master ) in the DUW and make it master in order to connect external alarm with SAU.

The following cabinets and the duw in the network.

RBS 6301
RBS 6102
RBS 6101

DUW 31
DUW 41


Any leads on this subject bro please