Thanks my friend for the help.
I solved this issue few days ago. I used the report writer first as well but then I did it with SQL query in SW database because I wanted to be exactly sure what the result would be.
SELECT
Containers_AlertsAndReportsData.GroupMemberStatusDescription AS STATUS, COUNT(Containers_AlertsAndReportsData.GroupMemberStatusDescription) AS INFOSCREENS
FROM Containers_AlertsAndReportsData
WHERE Containers_AlertsAndReportsData.GroupName='INFOSCREENS'
group by Containers_AlertsAndReportsData.GroupMemberStatusDescription
and the result was okay. I only need to create new report with that SQL sentence so I can see it in website as well