I have two flexi task. On the first flexi task assignee is a sharepoint group which has more than one members. now in the task form of the second flexi task I want to display the name of the group member who rejected or approved the task.
Top of my head, you should be able to analyze the All Approvers Comments by extracting each entry into a collection workflow variable and use a foreach to go through each line.
Another way is to create a workflow on the Workflow Tasks, assuming the 1st flexitask is set to create separate task for each approver. This Workflow Tasks workflow then would need to track back the item it was created from and update that item with the outcome of the task. A variation would be to have this Workflow Tasks workflow to create an entry in a helper list, which then is checked by the first workflow which created the flexitask. In either way the Workflow Tasks need to know which item ID was involved (e.g. by putting the item ID at the start of the task name).