Average Reaction Time Feedback

I’m looking to provide feedback to participants about their average reaction time at the end of a practice block in Superlab 5. I have been able to get as far as using a timer parameter to display their reaction time for a single trial or their cumulative reaction time for all trials (i.e. the sum of their reaction time across all practice trials). I know that you can use a Collection of Trials parameter to calculate average RT, but because that parameter also contains other options (e.g. collection is full), it seems like I can’t display it to the participant in the same way as other parameters, by using the $(parameter) notation. Is there a way to display average RT from a collection of trials parameter? Or is there a way to get Superlab to perform a calculation on a timer parameter (i.e. divide the cumulative RT by the number of trials) before it displays? Thanks!