How can I do a DISTINCT on one column only, within a 4 level JOIN ?

Here's the example;

One of the tables I'm joining is called 'seasons' with 3 columns: 'season' 'start_date' 'end_date'.

In the main table there is a column 'season' where the value is either 'basic', 'shoulder' or 'peak'.

In the 'seasons' table, the 'season' column is also one of the 3 mentioned season types. However, there is usually more than one line for the same season but with different date periods.

Now when I use this query that I created with Access, it retrieves the same record from the 'main' table multiple times! I now figured out it's because it's counting how many season periods there are, even though they're all with the same season type...