Numbering Shapes by Shape Master

[Mark]

Hi:

I'm trying to have my shapes auto-numbered based on the Master type.
For example, if my stencil contains a master of a box and a circle,
I'd like the first Box I drop to be numbered something like "B-1", the
second "B-2". If I then drop a cicle, I'd like it to be "C-1", and
the next box to be "B-3".

I can auto-number the shapes by adding an Object ID field to the
shape text, but that method numbers all the shapes sequentially (in
the example above, I'd get "B-1", "B-2", "C-3", "B-4".

Is there a way to do this internal to the stencil itself? I'd like to
try to avoid using template-based formulae, or external apps.

Thanks,
Mark

(e-mail address removed)

(this was also posted in alt.visio)