Integrate policies

Why do you want to integrate them in an unique document? We think that it is better if you have a high level policy for the ISMS (with strategic intention, objectives, etc) and detailed policies for control access, backups, etc. If you have an unique document, it can be extensive and uncomfortable to read. 
Finally, I think that this article can be very interesting for you "One Information Security Policy, or several policies?" : 
https://advisera.com/27001academy/blog/2013/06/18/one-information-security-policy-or-several-policies/
And also can be interesting for you this article: “Information security policy – how detailed should it be?” : https://advisera.com/27001academy/blog/2010/05/26/information-security-policy-how-detailed-should-it-be/