beginBitmapFill with two images?

I have a program that responds to mouse clicks on the stage. Each time the user clicks it draws a horizontal or vertical rectangle composed of 32x32 squares to that point. Currently I am doing the following to fill in the rectangle with a png i have made.

                // Draw segment
                var myBitmap:BitmapData = new BitmapData(32, 32, false);      
                g.drawRect(pX, pY, rHeight, rWidth);

However if it is possible I would like to draw a different png at the point when a vertical rectangle links with a horizontal. So is there a way I can draw a png to the first square of the rectangle and tile the remaining with a different tile?