PIM-1437 : Separate variant groups and groups

Bug fix: [yes|no]
Feature addition: [yes]
Backwards compatibility break: [no]
Unit test passes: [yes|no]
Behat scenarios passes: [yes|no]
Checkstyle issues: [yes|no]*
Documentation PR: [link to the documentation PR if there is one]
Fixes the following jira:
 - PIM-1437
 - PIM-1456