Merged table headers

[HB__BH]

Dear All,

Is there an easy way to make merged headers for a table in the sample you can see in the pictures? Now the "headers' are only text boxes and don't move simultaneously with the table.

I have already checked previous threads regarding the topic, however at first try a matrix visual couldn't bring the right solution. Non-paid Invoice (EUR) and (Not Invoiced (EUR), CCD (EUR)) columns come from different tables.