Is it possible to create custom shaped balloons from pre-made
blocks? I would like to have a splt line square or a 3-number
divided pie balloon, both with the ability to link to custom
properties. The latter would be used in lieu of stacked balloons to
save drawing real estate. One shape would symbolize a certain
device while another shape for a different device.
You can use notes, and link their properties just like balloons.
Notes are very versatile, and can do almost everything you asked
above. The only drawback is that they only point to one object, so
you cannot incorporate multiple balloons like a stacked