The Line node uses spreads for generating a line point by point, but how i have to proceed to draw more than 1 line without any connection between the lines? Just using one line node.

That is what the binsize pin is for. fill it with a spread to specify how many points belong to each line. So if you feed the line 10 points you could feed the binsize pin a spread of 5, 3, 2 to specify that the first line is made up of the first 5 points, the second line is made up of the second 3 points and the last line is made up of the remaining 2 points.

A negativ binsize (not spreaded) gives the amount of lines which the points are divided up to. So if you give the line 9 points and a binsize of -3 you will get 3 lines, each using 3 consecutive points.