Knowledge workflow approvals routing based on Articles

We have a specific Business Requirement:

A single shared content type (E.g., HR Policy) will be used across 20+ Departments/BU's. Separate content type cannot be created per department because:

Many policy details are common/shared across departments. Maintaining 20+ separate content types for HR Policy purpose would create unnecessary administration overhead. Similar requirements applies to other content types like Guidance, Solution etc.

To support this model, the content type will contain multiple sections, (e.g., Title, Summary, Common Details,Dept1 Details, Dept2 Details…)

Approval workflow Requirements:

Each department has its own designated knowledge reviewers. The requirement is to route approvals task only to the reviewers of the department the article relates to. E.g., Article containing Dept1 details should be routed only to Dept1 reviewers, Articles containing Dept2 details should be routed only to Dept2 reviewers etc.