For anyone interested, since the help here is clearly limited:
As there seems to be no way to create a wrapper, I solved the problem with:
# Method
".row:nth-child(NUMBER)"
# Applied to my accordion this looks like:
jQuery(document).on("click touchstart", ".accordion-toggle-3", function() { jQuery(".row:nth-child(21)").nextUntil(".row:nth-child(25)").slideToggle();
Here .accordion-toggle-3 is the class of the element to be clicked to execute the toggle. This can also be bound to an event changing e.g. a + into a - for showing the current state (open/closed).
Good luck!