Go to Mailing Lists
Click on Select Mailing and select the one you want
Click on Manage List next to the dropdown
Click on List Settings
Uncheck the box and click Update Settings
Click on Contacts in Navigation Bar
Click on Create New and select New Group
Title new group "First xxx"(or whatever group name you want to use) and click Create Group
Click OK
Click the All contacts dropdown menu and click name of Mailing list
On the right change the Number of contacts viewed to a number higher than your list or 1000, if your list is over 1000.
Next to each Last Name check the box to select all you want to move to the new group
At the top click on Assign to Group
Click the Dropdown and select "First xxx" (or whatever you called your group) and click on Assign Group
Click Ok
You are now in the group you created
Click Manage Group
Click Group Settings
Check the Box at the top
Save Update
Click the dropdown menu and select the mailing list
Click Manage Group
Click Group Settings
Check the Box at the top
Save Update
Both lists are now under Mailing List again and out of the contacts.
Now you can go and enroll the list you created into your automation