Can someone explain/translate what this credit 聯合導演 'union director' means, as distinguished from a regular director's credit? Does this simple imply that a director assigned due to union contract? Or something completely different?
e.g.,
標題: 沙灘仔與周師奶 - Royal scoundrel / - 導演, 杜琪峰 ; 聯合導演, 戚其義.
出品/出版: 香港 : 新藝城影業有限公司 ; 百嘉峰影業公司, 1991. 金公主[發行] ; 寰亞電影發行有限公司[發行] ; 百嘉峰影業公司[攝製], 1991 [首映].
詳情: 有聲, 彩色.
備註: II ; TELA.

the first symbol 聯 means "associate", so I think it means "associate director".

The associate director is an usual job in asian film industry, he is delegated by the director of the film to direct several segments of the movie under his supervision.

The associate director is not the assistant director nor the "helping" director.

well, this is my humble opinion...

Ah, makes more sense. Thanks.