Steel members are not automatically placed into design groups. They are however, automatically put into groups, primarily for editing purposes. In this way, individual groups can be selected and displayed graphically so that their properties can be changed as a group in the properties window.
If required, grouping can also (optionally) be utilized in order to design steel member types according to their groups.
In order to use grouping for this second purpose, you should first ensure that your groups are configured so that each group only contains those members that you intend to eventually have the same section size applied.
Note: Grouped design is optional and can be activated if required, via Design Options> Design Groups
Note: A fixed set of rules are initially used to determine the automatic member grouping: for example beams are designated as either direction 1 or direction 2, are of a similar span, material grade and construction type, columns have the same number of stacks etc. You can manually edit groups.