*you are with your team can generate the integration of your company management system,
*we can suppose that QA is former /recent management representative for the 3 STDs,. hence you have copy of all DOCs.
*you should refer to all processes / procedures in your company; you should identify each reference clause number in each process /procedure relevant to std. ; remember that one process can reflect many references clauses for ISO 9001-ISO 14001-ISO 45001 ---etc.--including evidenced generated records also ;
* hence after making the studies above' you should refer to ISO 9001 reference clauses ; making them in table & schedule each process as referenced objective evidence in the same table ; you will find also a comparison table in the end of ISO 14001 & ISO 45001 standards which indicate the 9001 ref., ; they are now have the same in 2015 versions & 2018 " for 45001 " ; most clauses number of 9001 could hold the same # of the rest of 2 STDs ' hence you can amend your check list to define the rest of process /procedure reference ' including the objective generated record ;
*this technic above has added value; not only for integration but also to make effective gap analysis