Nested Contact Lists

Feature Request: Nested / Sub-Contact Lists

Problem
Contact lists are flat — there's no way to nest one list inside another. When a rule references a contact list (e.g. an exclusion list), any changes to that list require an admin to manually update the rule. This creates an ongoing bottleneck for non-technical team members who need to manage their own contact sets.

Request
Allow contact lists to include other lists as members, with parent lists dynamically resolving to the full combined set. Non-admin users should be able to update sublists without touching rules or automations.

Impact
A customer's reservations team can't self-serve their exclusion list today — every update requires looping in a technical admin. Sublists would remove that dependency entirely.