Do anybody know a voip soft-phone able to manage different voip numbers at the same time?

I have few Voip geographical numbers (1 uk and 2 italian local numbers) and I wish to manage all of them without using 3 different soft-phones as I do now. Which software offers me the possibility to this?
Apparently the premium version of X-Lite is able to do it but the free version gives me some connection problem so I don't dare to buy the premium one.

Anybody can help me?

Thanks a million!!!

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