The easiest way for you to implement this chart would be to create two data sources for each series containing absolutely the same sequence of category values:
1, 2, 3, Q1, 4, 5, 6, Q2, 7, Q3
and load them into the chart. You should simply make sure to provide the Q-values in the second series only by omitting the values for 1, 2, 3... and vice-versa: provide the 1, 2, 3 values in the first series only by omitting those for Q1, Q2...
I hope this helps.
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