A construction-kit system includes at least one primary-valve block (10), with at least two groups of connection lines (12, 14) interconnected at one point (16) via a connection line of one of the groups (12) to form a fluidic connection. At least two additional connection lines of the one group (12) are respectively connected to a corresponding connection line of the other group (14). At least three dummy components (18) are connected in the connection lines of the other group (14) for the insertion of predetermined valve components. At least two additional dummy components (20) are connected between a common connection line (14a) of the other group (14) and an additional respective corresponding connection line (14b) of the other group (14).