In Googleing this 'one party' issue as it pertains to Arizona law it appears that Arizona has a potential exception to 'one party consent' in a situation where there is a reasonable expectation of privacy in which case it may be necessary for all to be aware of the recording taking place.
Not at all sure what the full text of the applicable laws say or how it may apply in this specific situation. This is just what I Googled. Could be right, or wrong, or somewhere in between.
