You can specify that an individual file created by JCL or IDCAMS is to be accessed via Fileshare, or by a specific Fileshare server overriding the one specified in the Default Allocated Dataset Location.
In the DD or DEFINE command that creates it, use the extension %PCDSN (see the chapter Extensions to JCL and IDCAMS ) to specify a physical filename to override the default location - include the name of the Fileshare server in the path/filename you specify here.