Yes, you can group components together in Flux using the "Convert to Component" feature. This turns them into a single sublayout. To do this, follow these steps:

In order for the component group (or sublayout) to be usable in a project, it must have terminals for connections. If the components you've grouped don't already include terminals, you can add them in two ways:

Remember that sublayouts are a great way to reuse portions of a circuit that are consistent across multiple projects.

Source(s):

https://docs.flux.ai/reference/convert-to-part
https://docs.flux.ai/Introduction/walkthrough-3-parts

In Flux, the ground layer is automatically added, it just hides it by default so you can focus on the routing.

You can follow the steps below to show the ground layer:

Remember that it's advisable to enable the fill visibility after you've completed routing. Before you send the board for manufacturing, make sure to check all these steps.

Source(s):

https://docs.flux.ai/Introduction/walkthrough-7-routing-layout
https://docs.flux.ai/reference/reference-layer-view-control