Thanks for your reply, @hube2 – I ended up using the init hook as indicated in your example, and I also made use of the add_option() / get_option() functions to force the utility function to run only once, as described in this post. For any others who may stumble across this thread and need to do something similar (e.g. utility function to update the content of a field for all posts), this approach worked well for me.
