Is there a different naming convention for Additional Product Images?

Besides using _01, _02, _03, is there a different way to handle additional images? I do have Image Handler v3 installed and when I go to delete the incorrect additional images the products using those images for the main image is deleted.

Product model 123ABC I name the corresponding image
123ABC.jpg.

For its additional images I'll renamed them:
123ABC_01.jpg
123ABC_02.jpg
123ABC_03.jpg.

HERES THE PROBLEM

I have products named
123AB.
So product 123ABC's images are being pulled in as additional images for 123AB.

Is there a different way to name the images so they don't get pulled into a similar products page? The one constraint is that I cannot rename the model number to something else. Its a system that's been used for years by my company and can't be changed.

Hope this makes sense.
Thanks

I'm thinking of changing my naming convention all together actually. SO instead of using the products model number maybe a combination. Since there is too much similarity in product models in the inventory system I feel like this would be the best way. I'll try this and post after.

You could continue using the model number and simply add an underscore to the main product image (e.g. 123ABC_.jpg, 123AB_.jpg). That would make the models unique and you'd only have to rename the main image (all the additional images would still be matched).