@Parampal   High Level plan can be as follow:

Merge or move smaller application ( in terms of production data) into Bigger application.

For Rules:

1. Take Rules RAP from source and import into target.

For Data:

1. Identify the work and history tables. Move entire tables to target.

2.Identify the data/rows to be moved from common tables. (like attachment tables,  assignment tables). In target, merge with existing table. While merging, if the there are primary key conflicts, decision to be taken which records should be discarded and which needs to be preserved.

Note: This is difficult step and requires extensive application knowledge.

3. Identify DSS and other environment configuration which requires to be moved. RAP can be used to move these configurations.

Approach should be implemented in lower environments and tested properly for all scenarios.