Replace specific symbols in scatter plot in Illustrator

I am very new to Adobe Illustrator, so I apologize in advance if my question is offensively simple. To my excuse, I spent and failed to look for a solution online, even though I am sure I am not the first one to encounter the problem.

I created the following plot of the Austrian party positions over-time:

Now, I would like to change each symbol for which the party names end with 58 to something else (like an unfilled triangle); the ones with 63 to a second symbol and the ones with 56 to a third symbol. The idea would be to show how parties cluster on the plot, as a function of the specific election.

However, I can't figure out how to change the symbols without manually copy pasting something there. Any ideas?

UPDATE: I should have added earlier: AI does not recognize the circles as symbols, therefore the replace symbol option in the symbol panel does not work. Is there a way to get them recognized as symbols?

Answer

To easily replace objects I recommend installing and using the wonderful copyToMultipleObjects script by John Wundes.

To install opposite click on the link and save it to your desktop.

With Illustrator closed, navigate to your Illustrator's Script folder, which is in the following example location (the actual location will depend on your installation of Illustrator and language):

Windows: C:/Program Files/Adobe/Adobe Illustrator CC 2014/Presets/en_GB/Scripts

Mac OS: Applications/Adobe/Adobe Illustrator CC 2014/Presets/en_GB/Scripts

And paste a copy of the .js file into the folder and open Illustrator.

To use, have the new shape made and on the topmost layer/position above the shapes you want to replace.

Next select the shapes you want to replace and the shape you are replacing them with.

Navigate to File-> Scripts-> copyToMultipleObjects. Click yes to scale objects and you are done!