select
profiles.realname as User_Name,
sum(ba.added) as Hours_Worked
from
bugs_activity ba join user_group_map u on ba.who = u.user_id
join profiles on ba.who = profiles.userid
where
u.group_id = '15' and
ba.fieldid = '47' and
YEARweek(ba.bug_when) = YEARweek(CURRENT_DATE)
group by ba.who;
This query now can find the time for users in a group.
I have learned lot on this site from other users posts, thanks everyone.
Updated my original question with the script, with the script I figured out.