I have 3 tables cust vend and business table all table one common column and relationship to cust to business table and vend to Busines table

Question

I have 3 tables cust, vend and business table.  all table one common column and

relationship to cust table  to business table (Active) -- many to many relationship

and vend  table to Busines table. (ambiguity) - getting error.  how to achieve this.

Cust :  Attr grp, cust_num, acc grp, dimension

Vend: Attr grp, cust_num, acc grp, dimension

Business :  Domain, Attr grp, acc grp, dimension, severity (Measure)

How to create a active relationship for these tables?