Very good indeed, Antonio1986. There is one thing though. I think you didn't use the word "тоже" correctly. I recommend you subtitute it with "также". Examine these:

Ты тоже мой друг - You're my friend as well as another friend of mine. (Like you're my friend too)
Ты также мой друг - You're my friend in addition to everything else you're to me.

I think you sense the difference now.

However, I have to mind you that the word также sometimes have the same meaning as тоже, BUT тоже never has the meaning of также. I hope that was not too confusing.

Well, basically:

Ты также мой друг can mean the same thing as ты тоже мой друг. But ты тоже мой друг never has the sense of ты также мой друг

Finally, there is my alteration of the phrase you want to express in Russian. Just keep in mind that you're original attempt to do that is very good and you can go along with it if you like, just remember the "тоже-также" thing. What I offer here is slightly more refined version of it, in my opinion anyway

Вы мне также (и) друзья. Но если вы хотите, чтобы наши отношения были сугубо деловыми, тогда я буду относится к вам только как к клиентам