EDMCS Derived Property Creation for Aggregating Child Node Values

I'm looking for alternative approaches /thoughts for a requirement in EDMCS. The requirement is to include a Unique Nominal List (and related description) per Disclosure ID in an extract (that points to a hiearchy dislcosure mapping viewpoint), for example:

Disclosure ID	Unique Nominal List	Unique Nominal Description List
A	X,Y,Z,K,Q,P	X1,Y1,Z1,K1,Q1,P1
B	R,S,T,X	R1,S1,T1,X1

A simplified view of the hierarchy is:

Top Node
├─ FCCS Account 1
│  ├─ Disclosure ID A
│  │  ├─ Mapping (Nominal X,Y,Z)
│  │  └─ Mapping (Nominal X,Z)
│  └─ Disclosure ID B
│     ├─ Mapping (Nominal R,S)
│     └─ Mapping (Nominal R,T,X)
├─ FCCS Account 2
│  └─ Disclosure ID A
│     └─ Mapping (Nominal K,Q,P)