Data Model- Distinct Count of Vendors by Customer with Orders

[TuesdayApril]

I have the below two fact tables in my data model. Order Item Fact and Invoice Item Fact. They are filtered by the same dimensions except Order item Fact is filtered by Orders Dim and Invoice Item Fact has Invoice Dim.

• When I distinctcount vendors by customer with orders I get a cartisian error.
  
  
• I cannot do a both way relationship between Vendor and OIF or IIF because it introduces a relationship between Order Item Fact and Invoice Item Fact we do not want.
• Is there a function I can use in DAX counting only a both way relationship on Vendor and Account (customer)

Thank You in advance.

[Greg_Deckler]

@TuesdayApril Sorry, having trouble following, can you post sample data as text and expected output?
Not really enough information to go on, please first check if your issue is a common issue listed here: https://community.powerbi.com/t5/Community-Blog/Before-You-Post-Read-This/ba-p/1116882

Also, please see this post regarding How to Get Your Question Answered Quickly: https://community.powerbi.com/t5/Community-Blog/How-to-Get-Your-Question-Answered-Quickly/ba-p/38490

The most important parts are:
1. Sample data as text, use the table tool in the editing bar
2. Expected output from sample data
3. Explanation in words of how to get from 1. to 2.

[TuesdayApril]

Simple. I want distinct count of Vendor ID to display in the table above with  Account(Customer) and Sum Orders. What should the relationships be? Because Vendor filters both Fact tables a both way relationship that would make the calc work is not allowed.

Should I create a second Account and Vendor table for Order and Fact separately or is there a function I can use in DAX to make this relationship work?

[TuesdayApril]

Should I use 

'related table' to connect Vendor to Invoice and Orders, create a custom column