Is it possible to show only a few values from a cascading field using an automation script

[Kris]

 I have the following issue.

I have a cascading field with the following options and sub options

• A
  • 1a
  • 1b
• B
  • 2a
  • 2b
• C
  • 3a
  • 3b
• D
  • 4a
  • 4b

And I have a custom field  related to groups

• Group A
• Group B

I now want to setup the following automation rule

When I select Group A , I only want to see option A & B  from the cascading field

When I select Group B, I only want to see option C & D from the cascading field

(I still need to be able  select the sub options that belongs to the options)

Can I configurate this with automations rules  or can I do this with scriptrunner?

Or is this not possible at all