If you look at the command's description and the description of the input parameter(s) in the tool-tip, it clearly says that it expects a comma ',' separated list of hosts.
Description for Command "Create Export":
Creates an NFS export and sets it up. Comma separated list may be supplied to grant read-only, read-write and root privileges to specified hosts.
The Path parameter refers to a persistent path that can be applied.
So it works as designed.
The delimiter used is ','.
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