I con't know of a way to do it from the Comcast Outlook web mail. You will probably need to log in to the Comcast Business Portal at »businessclass.comcast.net/
and select Manage Distribution Lists
from the Email section on the right side of the page.
Once there, you should be able to create whatever distribution lists you require.
Here ia a screen shot of the page for creating distribution lists:
And FYI, you don't have to use the Comcast Outlook webmail unless that is your preference. You can use POP3, IMAP, SMTP from standalone email clients if you wish:
Don't use the servers you see in the screen shot above; log into your account and use the settings that are specific for your account and location (the email servers are different for different locations).--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.