Custom Module & Relationshipbuilder for VTiger is an extension that allows crm administrators to create custom modules within few clicks. All custom modules are created following strict VTiger standards. In addition, the relationship builder allows crm admin to link together existing modules as well as new custom modules. It supports 1:1, 1:M and M:M relationships.
How to Add Custom 1:M Relationship
Go to Menu > Settings > CRM Settings > Extension Pack > Custom Module Builder.
Click on “1:M Relationship” button to add a relation.
Select the Primary module you want to link to multiple records of another module.
Select the Child/Related module you want to link to the single primary module.
Select the block of records from secondary module in which you want the field to be displayed.
You can see the information in the Secondary module that is populated form the Primary module.