How do i change my "from adress" to a group alias instead of my primary email when mail merging?

How do i change my "from adress" to a group alias instead of my primary email when mail merging?

When mail merging I would like the "from address" of the emails to be a group alias instead of my primary address. How do I change it to be my group alias? For context the attached image is my view od the tool.