Grouping Email Address (Best Practice)

Hello,
I will like to know the best practice for grouping email addresses in a table.

We have a basic table that has email address for admin users. Which goes thus

CLIENTS EMAIL

emailID int
username: varchar 20
Client_email varchar 150


The Above table is for our admin users. Enabling them to send out emails to clients. Based on their bills.

We have a second table for mass mailing. Which has emails in groups. Each group is based on the above entry. And groups could range from 5 users up to 100,000 users.

Whats the best way to implement this.

Do I create a seperate column for each email entry, knowing that this table would be extremely big, with a lot of repeated values, ie username etc. Or group them TOGETHER as varchar(max)

PLEASE ADVICE, best practices

thanks
Mary




Yes O !