Approvals can be setup (Individual or Group in "Approval Mappings" form) automatically and can be assigned to the group as per the mappings defined in Approval mapping form.
You can setup Group approval in 'Approval Mappings' form for each phase whichever you are interested. When you setup group approval then if all the members in the group have functional role as an 'Change Approver' then everyone will be able to approve the request whichever is assigned to this group.If you are interested in only one member from the group to approve the request then you provide functional role as 'Change Approver' to that specific user only , so that other users from that group will not be able to approve the request.
The users will be able to see the list of approvers in the Approval table of the change request. If the request is approved then user can check the approval status by selecting value as 'Approved' in Show field of Approval table in change request (ITSM 7.6).
It looks like you can amend the Approval Engine settings for the change process to say either 'One Must Sign' or 'All Must Sign'
Open the form AP:Process Definition and search for 'Process' = "Change Level IA - Implementation" or whatever process you're interested in.In the 'If Multiple Approvers' field it should say "All Must Sign". Setting it to "One Must Sign" means that only one approver in each group needs to approve on behalf of the rest.
See page 219 in the v7.5 Remedy Approval Server Guide.