hierarchical data/layer structures
the data hierarchy

```
* group1
  * item1
  * item2
  * item3
* group2
  * item1
  * item2
  * item3
…
```

could be matched to the following layer hierarchy

```
* layergroupA
   * layergroup1
   * layergroup2
   * layergroup3
* layergroupB
   * layergroup1
   * layergroup2
   * layergroup3
```

meaning that {placeholders} will only be replaced on the respective level of the hierarchy
