You can define a calculation that inserts the needed formatting. You should be able to adapt the expression used in this Knowledge Base article: http://help.filemaker.com/app/answers/detail/a_id/2938/kw/decimal%20format
Thank you Phil!
I will give it a try. Should I just select those calculation fields as reference to the graphic instead of the original ones?
I'm wondering if the result of the calculation is going to make any problem to the graphic..
I should have thought this one through better. I am not sure that such will work here. If I were you, I'd test this and see if it works. And please report your findings back here so others will know.
I'd test this first with a text result, then with a number result type just to try all possible variations...