You’d use both “Exclude laps” and “Skip laps” options as follows:
Start type = Individual
Multiple distances = On
Record lap times = On
Beginners: 7 laps
Experts: 7 laps
Customize lap names = On
Start = S1 start
Lap 1 = Stage 1
Lap 2 = S2 start
Lap 3 = Stage 2
Lap 4 = S3 start
Lap 5 = Stage 3
Lap 6 = S4 start
Lap 7 = Stage 4
Skip laps = On
Beginners: Skip = S3 start, Stage 3, S4 start, Stage 4
Experts: Skip = None
Exclude laps = On
Beginners: Exclude = S2 start
ExpertsL Exclude = S2 start, S3 start, S4 start
Timing mode = Multi-device splits
Device #1 records = S1 start, S2 start, S3 start, S4 start
Device #2 records = Stage 1, Stage 2, Stage 3, Stage 4