How to dynamically change color of lines joining child nodes?

Hi,
how can I dynamically change the color of line joining the nodes based on some property?
For example:
```
+ ROOT
|
+ child A; props: change_color: true
| |
| + child A-2; props: change_color: true
| |
| + child A-3; props: change_color: true
|
+ child B
```
for given tree I would like to dynamically change color of lines for childs from A-3 up to A and only them (they have property "change_color" set to true), how can I do that?