STRING in a expression.... how to transform it?

[#1]

I have a string made in this way:

"14|13|5"

I would like to convert this string by using a condition....

for example:  If one of the value is > 10 then transorm it in A else in B:

I would like to have as a result:

"A|A|B"

Is it possible ?

Thanks in advance

[#2]

All this stuff ... is to show ... the Amount of sales (or whatever) for each region by using the google api chart ...

I would like to show a gradient geo-chart ....

It's going to be ...very difficult