Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

The list of prominent Australians who have been called in as troubleshooters includes retired judges Ian Callinan, Geoffrey Davies and Julie Dodds-Streeton at CBA; former Victorian premier Jeff Kennett at Coles; former chief commissioner of Victoria Police Ken Lay at Australia Post; and former prudential regulator Jeff Carmichael at CBA.

Answer: position_held: Ken Lay, chief commissioner of Victoria Police