Fields on Playbook activity should be editable only to Assignment group/Assigned to users in Workspa

[Yathvika]

Hi Community,

Currently in the Playbook created the Custom Activity and showing the Task(Fields and Variables) in playbook card with Update and Mark Complete Buttons.

I would require making these fields editable only to appropriate Task Assignment groups/Assigned to Agent. So how can I achieve this so that the users not from that group/assigned to will see the fields and variables as greyed-out.

Regards,
Ratna Jyothi.