We have prepared the sample based on your requirement to bind an observablecollection inside another observablecollection. We Couldn’t able to understand your query clearly. Please let us know you are using the collection like mentioned in the below code snippet, have attached the prepared sample in below .
public ObservableCollection<ObservableCollection<Parent>> Collection = new ObservableCollection<ObservableCollection<Parent>>();
In this case, we can’t bind the collection to the ItemSource in xaml based on index. We can able to set the ItemSource in code behind based on index. We have attached the sample please modified the sample as per your requirement or else please provide the more details about your requirement.
Please let us know, if you require further assistance on this.