I guess you're using the Extend X/Y Size to Area feature. I’m afraid, that there’s no fully automatic way of splitting such area into multiple arrays, but that’s possible with some tweaks of the base spline copy.
To decide, which vertex should “break” the array, using a X Spline would be the recommendable way – the Y Size you set just by a value as you can still use the Clipping Area to maintain the shape – you should just break vertices on the X Spline at points where you need to “reset it”. Attaching a sample scene,
Hope you’ll find it useful.