linux stress, impose work on specific disks

Have a server running centos 7.6, and it has 4 ssd's as Raid-0 mounted as /scratch/ I have the linux program stress-1.0.4-16 and I just learned stress-ng existed. Is there a way with stress to tell it to do I/O operations to stress a specific set of disks such as my 4 disk Raid-0? Or does it only work on whatever the root file system is such as /tmp? And if that's the case I've done systemctl enable tmp.mount which means the /tmp folder is no longer on disk negating the disk i/o function of stress ?