Add groups as a configurable entity for Approvals

Problem Definition

The current implementation of approvals either requires all of the approvers to provide their approval, or a fixed number out of a set of users.
In certain organisations, approval responsibility does not reside with individuals, but with groups (read, departments within the organisation).
A requirement in such an organisation could be, that in order for an approval to go through, multiple groups are required to provide their approval.
From within those groups, there are separate sets of users that can provide approval, though each group only requires to provide an "x" amount of approvals.

Suggested Solution

Add an additional option in the current approval feature.
The "Get approvers from" option should not only work off a multi user picker custom field, but also a multi group picker custom field.
The "Consider approved after" option should allow for a configuration where a number of approvers per group can be set, next to the "all" option as currently available.

Why this is important

Change management can rely on multiple departments within an organisation prior to changes being allowed to get pushed through.
The current implementation of the approval feature does not allow for a differentiation of user groups, reflecting these different departments within the organisation. 

Workaround 

Instead of having multiple groups required to approve a request in a single step, it is possible to make several statuses and approvals per status moving the approval process from one department to another.
This is a very linear approach, and could prove to cause (several) bottlenecks to occur within the change process when one department is quicker to approve than another.