Subsetting error - Select tags are missing

Products

• CA Test Data Manager (Data Finder / Grid Tools)

Issue/Introduction

I have 2 tables user1 and user2, and I am creating a subset to a user3  table. The tables are not mapped in sql (with relationships), because I have both tables in my register tables

When I try to create my data pool from my subset, I get this message. 

Environment

Release : 4.9

Component : Subset

Cause

Subset on one table is not supported

Resolution

Subset on one table and data generation is not supported. You need to create a relationship in Subset and Subset both tables.