Good news is yes it can, just follow these steps. Setup the Startn field’s “Calculation for task and group summary rows” to Rollup or Use formula from details. This sets the summary task Startn date. Now you have two options:
Show a bar indicator: Select Bar Styles (Format tab, Format, Bar Styles). Add a format line under the Summary line using the Insert Row on the top of the dialog box. Name it (like Startn Summary). Set the From and To columns both to Startn. Now on the bottom of the dialog box, set the Start shape and color to your desired visual.
Display the Startn field: While in the Bar Style dialog box, select the Summary row, select the Text tab on the bottom of the dialog box, and select the Startn field where you want it to display (probably Left).