This is not easily doable in RME 4.0. While you can disable the system config fetch and polling jobs under RME > Admin > Config Mgmt > Collection Settings, you cannot create a Sync Archive job for a dynamic device group. So, if your network is static, and you are not adding or deleting devices, then go to RME > Config Mgmt > Archive Mgmt > Sync Archive, and create a new periodic job to fetch the configs from the desired devices. This list of devices can only be changed manually, though.