You should go with individually for EMS & OHSAS, both standards has different area,scope and impacts , integrated management system will be no that much effective.
And also let us know if you have not finalized the service provider for certification services, we also deal with all major standards, have good enough team of consultants & Lead Auditors.
If interested you may contact us via mail/mobile for further discussions so that timely we can award the certificates and company may use new tag lines on new year calenders/stationery and other important places and materials .
+91- 96707- 66-888
5th December 2016 From India, Lucknow