Aggregation accross tables

Dear all,

I have a huge Data Model with 30 Tables linked via Keys (Hash-values) to a fact table. The fact table only contains the keys and no additional data and is therefore hidden. Transactial Data e.g. the values are part of an dimension same as master data tables.

It looks a bit like that 

Table FACT:

ID_A

ID_B

ID_C

Table A:

ID_A

Info_1

Info_2

Info_3

Table B:

ID_B

Info_4

Value_1

Value_2

Table C:
ID_C

Info_5

Info_6

We are having multiple hunderets of million of rows. Right now the data model is setup as DirectQuerry since import is not possible.

I was thinking of Aggregation but was not able to build something like that:

AggTable D via SQL Import:

Info_1

Info_5

SUM(VALUE_1)

Unfortunately I am not able to link Info_1 from Table1 with the AggTable due to an N:M relationship. Any Idea if on how to solve that?