Set Environment for range of addresses

I want to disable logging for a range of LAN addresses. I can set an environment
variable for a single address like so:

SetEnvIf Remote_Addr "192.168.0.1" dontlog

That works fine. I can also set multiple addresses if I enter a line for each
one, but if I try to set a range of addresses thus:

SetEnvIf Remote_Addr "192.168.0.0/16" dontlog

it doesn't work. Am I asking the impossible?
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Crash