Is there any API to add or remove users from BPM Approval Group?

Summary:

Is there any REST API to add or remove users from BPM Approval Group?

Content (required):

We have got almost all of our User Provisioning fully automated over ERP Cloud + VBCS App Extensions + ATP APEX App, based on a single access request.

However we are facing issues with manual interventions required for "Approval Groups". Someone has to manually add and remove users from various Approval Groups. (Non-BPM seeded workflows can only work with Approval Groups and not Application Roles)

Is there an API to add and remove users from "Approval Groups" in BPM?

Version (include the version you are using, if applicable):