Multiple Approvals based on selected items in custom field

[Ian Johnsen]

Multiple Approvals based on selected items in custom field.

Example:

5 Approvers: Ian, Jason, Joe, Curtis, Chris

5 items in custom field: Billing, Accounting, Finance, Sales, Marketing

1. Ian Approves Billing
2. Jason Approves Accounting
3. Joe Approves Finance
4. Curtis Approves Sales
5. Chris Approves Marketing

User selects Billing and Finance. 

Ian and Joe get a Button to Approve/Decline. 

Accounting, Sales and Marketing not selected and Jira not force an Approval from those people.

How do we set this up?

Thanks!