if I understand correctly, you have a table with invoice items and seperate items are to be approved by different people, e.g.:
Now you want to assign the parallel task to all users, in this case: admin, marek and simon.
you can use an "assign data" step to create a global variable of type "User from group" (use group "public" and check "list variable") which contains all users. Then, assign the parallel task to this GV.
The assign data step should look like this:
||Document Index Data
As parallel tasks finish automatically when all users completed their tasks, you should not need any cancel conditions.
Hope this helps.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant