To modify multiple policies at the same time, you can batch requests with
batchModify.
Requests can only be batched together if the meet all the following criteria:
Refer to the same target resource (Organizational Unit)
Share the same namespace (schemas differ only on the leaf).
Example: You can batch chrome.devices.A and chrome.devices.B, but not
chrome.devices.A and chrome.devices.managedGuest.B.
If schemas are keyed, the same keys must be present, but can have different values.
Example: You can modify settings of different printers in the same
Organizational Unit.