How to assign invoices to manually created assets as per business requirement

Summary:

There are 3 steps to capitalize CIP assets in PPM

1. Create manual assets using standard method- Projects→ Assets→ Capitalize Assets→ Create and Assign Assets in Excel
2. Project→ Assets→ Capitalize Assets→ Generate Asset Lines
3. Assign Assets to asset lines (multiple invoices) to the manual assets (got created in step1)
   1. Single invoice→ single assets
   2. Multiple invoices→ single assets
   3. Multiple invoices→ split the amount in multiple assets
      

Step 3 is decided by business, there is no fix rule, hence looking for some excel to upload, which can have manual asset details, asset lines detail with splitting percentage and assignment should happen as per excel, currently this is manual process which takes lots of time and effort.