The following technique will appear to change the line color of a rectangle, rounded rectangle, circle, etc. with the use of a tag.
The way to do this is to create the intended object and choose no border, then add another similarly shaped object behind it, slightly larger; also choose no border, and use a color animation to change the color of that object, giving the appearance of the front object having its outline change color with an integer tag.
It is also possible to use the same technique for rectangles using, instead of the back rectangle object, 4 unique line objects with color animation and brought to the front. These unique line segments will then become the edges of the target rectangle object, the color of which can be changed with an integer tag.