Activiti 6:Add new task instance to multi instance sub task or multi instance sub process at runtime

[svadaviya]

How can we achieve creation of a new user task instance to multi sub process process or multi instance user task at run time.

For example, Process is started and with multi instance user task lets say 3 user task instance is created and now user want to add one more task to that multi instance sub process instace or multi instance user task so that total user task will be 4 for that multi instance activiti.

Any help will be really apprreciated.

Thanks in advance