Yes, you will have to switch to "multiple" mode first.
You can do this with the Set-PowerCLIConfiguration cmdlet and the DefaultVIServerMode switch.
Then you connect to all the vSphere servers you need to use. You can check by displaying the following variable
$global:defaultVIServers
Your script will now run against all the connected servers,
An alternative is to connect all your vCenters in linked mode.
