Event Subtitle

Hi
I want to add a subtitle to my columns.
Currently the columns of the timetable represent the room where several events will be held over a period of time. Each room is also a topic stream.
So, for example room 1 has 3 events and the stream is “Policy”. Currently I have the room name but can’t add another subtitle to show the stream name.
The streams are not fixed to the same room, so as per the above example, the policy stream also occurs on a different day in another room.

The streams are also categories so essentially I want to show the category name in the table.

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