hoopsnake with multiple starting (and feedback) data

Hello!

I want to create a reciprocal structure unit, and designed an algorithm like this

http://www.grasshopper3d.com/forum/topics/construct-a-closest-point...

Now my file is like this

quite complicated. So I wonder whether I can do it with Hoopsnake, repeating process 1 for 4 times.

But the process involves 3 different starting input (in Circle 2), which is like this

Input a is the origin of the first rod (O1), Input b is to determine the direction of A1-O2, and Input c is the direction of the first rod (vector O1-A1).

I wonder how these 3 starting data can be calculated respectively in the iterations? Perhaps this involves some manipulation of data tree?

Can anyone give some suggestions? Thank you in advance for any help!