[Stagger with array parameter to timeline.add()]

Hi, in GSAP v2 it was possible to add nested timelines to a main timeline with a stagger by specifying two additional parameters like so:

const timelines = [tl1, tl2, tl3];
const mainTimeline = new TimelineMax(...);

mainTimeline.add(timelines, 0, 'start', 0.1);

How can I achieve a stagger when adding a possibly unknown number of nested timelines in GSAP v3? It seems that this functionality has been abandoned since timeline.add() only takes 2 parameters now.