Dynamic Parallel Processing using Rule

Hello,

I am using a User Decision within a Block (ParForEach type) step to send work-items to multiple Approvers parallelly.

For this I have created a Multi-line container LI_APPROVERS and bound &LI_APPROVERS[&_WF_PARFOREACH_INDEX&]& to &_LI_APPROVERS_LINE& in the "Parallel Processing" tab of the Block.

Now in User Decision I am using Agent as Expression = &_LI_APPROVERS_LINE&. This is working perfectly fine if I fetch the values in LI_APPROVERS via a background method before "Block" step is executed.

I want to know if we can do this using a "Rule" within the User Decision? Meaning approvers are determined by the Rule(through a FM) at the run time instead of fetching them beforehand. I created a custom Rule and tried passing it under Agents but it didn't work. I do not know what bindings need to be done and how each line will be passed to User Decision to create a work-item for each user.

Or

I should remove the Block step completely and directly use the User Decision Task with Parallel Processing option under Miscellaneous tab?

Can someone please explain how to achieve this using a Rule and exactly what bindings are required.

Thanks.