Help creating several closed polylines from .csv file

Hello GH group!

May somebody help me with this problem please!
I created a ptos.csv file, whit data organized by columns where:

1st,2th and 3th columns are the values of the coordinates of each point.
4th colum is a number that works as sequencer and discriminator of the closed polygons. Is the key number that let group the points in order to generate the independent closed polygons

Several times, the points works as part of overlapping boundaries for two closed polygonal polylines.

I am attaching a polylines.jpg as demo showing how have to looks like the final result, as same as the ptos.csv file whit the raw data. (Later I will give the colour and hatch.)

But I am stuck in this point: how to create those independent closed polylines?

Thanks a lot.