You can use zmprov and redirect a text file as input. For example, create a file called commands.txt
addDistributionListMember
list@domain.com member@domain.com
with a line for each member for each list you with to create.
Once you've done that, as the zimbra user you can run "zmprov < commands.txt" and it will execute those commands all in one run.
You can use "zmprov help list" for other distribution list commands.