I am unable to import data from my source module to target module because data in source module is under list item whereas in the target module it is under hierarchical line items. The source module has 79 lakh cells under each line item which needs to be mapped into 600 source module list items, it needs to find the correct combination of 3 list items. When I tried for only 10 data cells, one of which matched the 3 layers of hierarchical list items, Anaplan was able to automatically match the list items to the corresponding line items but it took time to process. In case of the huge 79 lakh it takes half an hour to import at the end of which it shows it wasn't able to find any of the line items in the target.
If you create a line item subset of you target line items, you should be able to create a system module, mapping the souece list as a dimension with a line item formatted as the line item subset. You then map the list items to the line items. You can then use a SUM formula to bring the data through without the need for an import
If the structures are the other way around, then the formula to use would be a LOOKUP
David's solution would still work, if you can stage the data in the target model with a module with similar structure as source module (from the hub) and transform it to target module structure as outlined in David's post.
However you would need to consider data volume before deciding on the right approach.