The only way I can think of is place these specific machines in a dedicated datastore, and enable storage io control on that datastore.
I agree as well. Likely the OP has multiple datastores in which case a datastore cluster with storage IO like sjesse mentioned would work.
One item though, this is an unusual request. Typically, VDI doesn't need to have this limit in place as dedicated storage is in place. This could be an over subscription issue on the storage I/O or perhaps a specific app generating the I/O. What is the behavior you are seeing that requires limiting the I/O?
Simply, we would not want users to create unnecessary load on the storage.
By the way, we use vSAN.
Sounds like you will be mixing VDI and Prod workloads on the vSAN. If you are running version 6.2 or higher, VMware introduced the IOPS limit per object feature.
Since this is based on the application of a storage policy to limit IO, it would be simple to apply the storage policy to your parent VM. One word of warning is to test, test, and test again on performance. It is very easy to starve VMs to the point of non-function when implementing policies such as this.
Here is a direct doc link from VMware for vSAN Storage Policy Setup: Link