"Join multiple CSV"

Suppose 3 CSV-files:

Events

id,event,day_id,city_id
1,work,1,2
2,work,2,3
3,theatre,2,1
4,work,3,2
5,work,4,1
6,work,5,3
7,trip,6,3
8,sport,7,1
9,relax,7,2

Weekdays

id,day
1,monday
2,tuesday
3,wednesday
4,thursday
5,friday
6,saturday,
7,sunday

Cities

id,city
1,paris
2,london
3,rome

Thanks to http://rapid-i.com/rapidforum/index.php/topic,9301.0.html I now know, how to join 2 CSVs in order to get the labels of another CSV instead of their IDs.
But how to join them if I have more than 2 CSV. The Join-operator can only by used to join 2 files.

This is the result I want:

1, work, monday, london
2, work, tuesday, rome
3, theatre, tuesday, paris