Hello list readers.

I'm constructing a dot chart in Stata using the graph dot command. I'd like to be able to edit
individual markers, so as to change their size, colour, as appropriate. However if I change one, all change. The following example is taken from the auto data often used for illustration purposes.

sysuse auto, clear
graph dot (count), over(rep78) over(foreign)

Is it possible to edit individual markers, or will I have to construct the graph differently? Thank you for any advice you can offer.