Can the from field be modified?
The from address for group emails is based on the group's email address. There are options to use sub-addressing, to include the sender's actual email address within the from email address.
In the Design area of your group Dashboard, there is an option to include the group name within the from address name.
NOTE: Occasionally, there can be issues with the group email address being associated with an individual's member name in the member's email clients. One way to rectify this is to enable sub-addressing for the group, so that each group message, from a particular member, comes from a distinct email address.