Modules & VBA :: Custom Record Navigation Buttons

To briefly explain my database; it is a bespoke referral management system within a hospital. Each record on the database contains patient demographic information, as well as information on their referral (i.e. date of referral, date of assessment, date of commencing treatment, discharge date etc.) Therefore, the same patient will appear multiple times in the database, with each separate record corresponding to a unique referral pathway.

The database forms are split to show patient information at the top, with referral information shown in a subform. I am trying to add navigation buttons to the subform that will allow the user to scroll through the referrals corresponding to the patient currently displayed on the main form.

Each patient has a uniquely identifiable number associated with them, and so it seems straightforward enough in my mind to have a button that will search for the record in the database where the patient's number matches the patient number of the current record, and where the referral date is minimum (for "First Referral"), maximum but less than current (for "Previous Referral"), minimum but greater than current (for "Next Referral"), and maximum (for "Last Referral").