Display two metrics for one value

Hi.

I am building an application for analysing race data. I have records that store a time score of a players. I know how to display average score grouped by User, sub-grouped by the player. I use bar graph for that.

I need to add a line of total average of all players on that chart so players can relate their scores to that average visually.
In spreadsheet I would create a second value series and choose line graph for it.

How could I achieve that in Softr charts?