The process that you are using is what we recommend federal contractors to follow because it impacts the data submitted to OFCCP. Since you are not reviewing the resumes when they arrive to the recruiting inbox; rather, your company process is to invite applicants to apply through your ATS in order to be considered for the position, you are on the right track. As long as you stick to that process and do not deviate from it, you would only submit data to OFCCP on applicants who meet the Internet Applicant rule. However, if you deviate from that process and accepted applicants from the recruiting inbox, then you would have to consider all of the applicants who used that mode of applying as well. Thus, continue using the process you have in place and do not deviate from it. As a friendly reminder, the qualifiers for the Internet Applicant Rule are: a person must express interest in an open position, receive consideration for that position, meet the basic qualifications for the job, and not withdraw from consideration.
You can use this OFCCP audit checklist to ensure you're doing what is required to maintain OFCCP's regulations including VEVRAA, Section 503, and EO 11246. Or request a demo to streamline your compliance and recruiting efforts.