you could use GROUP BY (look it up at www.mysql.com )
or you could use two tables.
I would use two tables.
Have all the groupnames in one table with unique ID.
Have the names in another table with unique ID, name, and groupID.
Then I'd find the id of the group I want, then look up all the names with that group ID.
But that's a bit involved, maybe. Is it purely coincidental that the group is also the first letter of the name?
Anyway, I suggest looking at the SELECT and GROUP BY statments at www.mysql.com