STEP 1
Use transaction GS03 - Display Set
GS03 - Display set: Initial Screen
STEP 2
Enter the set name you are looking for and
STEP 3
You can drill down by clicking on a group.
At last you find the accounts that are included in the group.
If you want to know in which group an account is included,
Enter the set name, then click on in the initial screen.
In the menu "Edit" select "Value/Interval" then "Find..."
Enter the account you are looking for and
The account is highlighted
Transaction GS03 is also usefull to identify all the sets related to one specific cost element.
In "utilities" option select "find values in sets".
Populate the adequate fields or use a variant already created. Click execute button.
The expected result should be a list of all the sets where the cost element is allocated to.