Metasequoia has a parent-child hierarchy function rather than grouping objects.
Pressing the '<' or '>' button in the object panel will make the object above it in the list the parent, or return it to the same hierarchy.

>Metasequoia has a parent-child hierarchy function rather than grouping objects.
>Pressing the '<' or '>' button in the object panel will make the object above it in the list the parent, or return it to the same hierarchy.

Yes but I need that a series of objects then work as one for instance when I move or scale them. Is it the same using hierarchies ?

Have you tried it yourself before asking this question? Try it out and then ask questions about anything you don't understand.