Approval Workflow Rule to the users which are in approval group in Parallel

Summary: Send a Leave request approval to group of users in parallel

Content (please ensure you mask any confidential information):

The requirement is to Send a Leave request approval to group of users in parallel and whoever act on the notification first it should be processed (Approve/Reject) and the transaction completes.

To Achieve this, we had created Application Role and assigned to group of users, but customer wants to use approval group which has multiple users.

Could anyone please confirm is there a way to push the leave request in parallel to the users which are in approval group or is that the only way to create application role to achieve this requirement?