For example, say you had a large pool of rooms and multiple groups of people showing up to an event, and want those groups to remain in separate blocks but don't want to specifically allocate inventory to each and every one of them. With accessible sub-blocks, you'd be able to continue to provide your sub-blocks a unique URL or group code, but configure them so when a guest in a sub-block books a room, it uses inventory from the main block to complete the booking but still books the room in the sub-block.
To create the accessible sub-block, you need to start with a previously-made sub-block, as the inventory controls won't show up until you do so.
When your sub-block is saved, click the "Inventory" section to begin.
As you can see from the image above, this "Barr" sub-block doesn't have any inventory created for it yet. If we used the sub-block URL to get to the Front-End and made a reservation, no hotels would show up in the Hotel Selection screen.
However, through accessible sub-blocks, we can set up this sub-block to have the same availability as if we were booking into the main-block.
This is accomplished by clicking the "Sub-block" drop-down, and selecting "Main Block", and clicking "Add Block".