Based on #19 there is a need for back reference block

[pouyakary]

Back Reference block was not added to Orchestra (and causes problems: #19) because there needed to be a good design for it. Back-reference can be as simple as:

The problem here is: there is no guarantee of safety of the number. So one might suggest using options to remove the possibility of unsafe numbers:

However this is also a very bad practice as one can not determine the group numbers within a range:

Another problem here is the name groups, in the future we can support named captures as:
(<name>something) and this can also be viewed as:

So clearly there is a need for a good idea towards implementing this