How to connect dots in a time series with multiple lines and measure points?

Hey everyone,
I measure the same value in multiple surveys on different timings and want to show the results per source, displayed by month as a time series with one line per source in one widget.
My problem is that the lines break if a measuring was not done. Is there a way to have connected lines for all?
Example: I have 6 sources who are 6 countries who should be my 6 lines.
I masure some countries 6 times a year e.g. in february, april, june, october, december and others only 3 times in february, june and october
(not always this timings, sometimes also one in feb, one in march, etc.) .
If i display my value now by country=time series (6 lines) and Date by Month = x,
the outcome is that the countries with only 3 measure points show only dots and only those with 6 show a line. I want to connect the dots but show only 3 values for those with 3 measure points and 6 values for those with 6 measure points.
Is there any way to get this 6 lines without breaks in one widget?
Thanks in advance.