A concatenated file should be opened only for input and should have organization SEQUENTIAL or LINE SEQUENTIAL. It is made up of separate components whose names are separated by the '+' character. On reading sequentially through such a file, when the end of one component is reached and another component is available, the next read will automatically return the first record of that component. On reaching the end of the last component, the AT END status is returned.
This parameter can be set globally only, that is under the tag [XFH-DEFAULT]. You cannot set the parameter for an individual file.