Showing Max date based on filtered services, possible subreport help needed

We created a caseload report for our clinicians to see all their clients and treatment plans. In addition, I want to be able to pull the most recent medication service, based on date and filtered by service codes that are identified as med services. Since I'm gathering two sets of data (service code and date), I wasn't sure how this would display most recent date. Here is my criteria for service codes:

{CLIENTSERVICES.SVC_ID} in [11, 20, 21, 22, 23, 24, 25, 29] and
{CLIENTSERVICES.DATE} = ??? (maximum)

Would this be a sub report I set within the existing report?