Shouldwehaveaposition是虚拟语气.省略了IF.本来的句子是

　　ifweshouldhaveaposition.如果我们会有个职位..

　　这里的should和虚拟语气句里的would意思一样.

　　比如ifiwereyou,iwouldgo.如果我是你,我就会走.

　　虚拟条件句的倒装

　　虚拟条件句的从句部分如果含有were,should,或had,可将if省略,再把were,should或had移到从句句首,实行倒装.

　　Weretheyherenow,theycouldhelpus.

　　=Iftheywereherenow,theycouldhelpus.

　　Hadyoucomeearlier,youwouldhavemethim

　　=Ifyouhadcomeearlier,youwouldhavemethim.

　　Shoulditrain,thecropswouldbesaved.

　　=Wereittorain,thecropswouldbesaved.