Although the positions may be similar, if the two positions are not the same title (or same position description), the pool from one cannot be used for the other. If the hiring official knows who they want to offer the position to, they may submit a Request for Waiver of Search/Recruitment; however these are not done often.
Instead of the waiver, you may post the position in OASys and send the posting information to the applicants you interviewed encouraging them to apply. You may provide general information and let them know you feel their skills, etc., may match this position if they are interested in applying. It is important to not convey that they “have” the job or are even guaranteed an interview; all applications still need to be reviewed.