Help by query

Hello list.

I have the following problem:

Example table Origin

*id | length | source | target*

1 25 33 45
2 100 45 60
3 12 22 11
4 78 60 55
5 20 24 60

Example Results: new table

*id | length | source | target | group | total length*

1 25 33 *45* 1 145
2 100 *45* *70* 1 145
3 12 22 11 3 12
4 78 * 60* 55 2 98
5 20 24 * 60* 2 98
6 20 30 *70* 1 145

Example Number variable >= 150

and I want to create groups of elements on two conditions.

source or target must match, since this indicates that touch

to group items with the first condition and that the sum of its length does
not exceed a given number

not be repeated elements in groups (The items can not be processed and
reprocessed)

Can someone help?

Thanks in advance

regards
Mario