Multiple replacements

[ssimop]

I wonder which is the fastest way to make multiple replacements in a string.
Let me be more specific. Suppose you have the string

s="this is the string to make replacements"

and you need to replace each occurrence of "i" to "u" and of "e" to "w".

Is it possible to do it with one command or you have to repeat find-replace twice (one for "i" and one for "e"?

Thanks in advance.