group(%gnGroup%) [using keys]
group tells Keyman that a new group has started. There are two sorts of groups: key processing groups, and context processing groups. Key processing groups can include context checking, but context processing groups cannot include key checking. Keyman will use first the group specified in the begin statement, and move from there onto other groups. The keystroke received by Keyman is the same for all groups with key processing.
To tell Keyman that the group should include key processing, you should include the using keys section of the statement; it that is left out, Keyman assumes the group checks the context only. The keystroke will remain the same during processing; you can have many groups that each use using keys, and the keystroke will be the same for all of them. If you leave out using keys, you have to also leave out the '+' and the keystroke.
gnGroup: The name of the new group.
group(main) using keys group(syllablecheck)
The group construct was introduced in Keyman 5.0.