Stacking callouts & balloons

In Composer 2018, is it possible to stack multiple balloons on a primary callout? For example, creating a callout and respective attachment for a bolt, then stacking balloons for a washer and nut adjacent to the primary balloon? I know this is possible in SolidWorks when creating drawings, there.

I've selected multiple callouts, to see if there are any "link" or "merge" properties or options, but don't see anything obvious.

Thank you -

SolidworksComposer