UPC Telefonie and Voip of the same telephone

Nextiva is a cloud based VoIP phone system, hosting lots of small and medium sized businesses nationwide. the provides UNLIMITED business calling for only $19.95 a month!! Click here for the detail about this promotion!!

Hello - I am completely new in the topic Voip, and therefore not surely into which forum I this question post am, I try it times here:

I have an Internet connection of UPC Vienna with sufficient range, as well as a UPC telephone connection including. Because the fees are nevertheless very expensive with UPC compared with alternative Telefonieanbietern, but the usual preselections (like 1031 Telekom, etc.) of UPC not certified procured themselves, I a Snom 300 as well as a Sipgate.at account.
Funzt well, of that quality am surprised I positive, and am annoyed now that I would not have used actually the fixed net option of the UPC at all - however too late… I am now bound one year…
Edit: the UPC account is “has a temperature to power” - cable connection, and not from Inode.

Now I have a contingent of 500 free minutes with UPC within Austria and/or. Europe, which I want to use also as point-exactly as possible. However I must telephone to also much to overseas, and there UPC is much too expensive, and it is used Sipgate.
For both entrances I have thus two different telephones (similar to hair dryer = UPC, IP hair dryer = sipgate), and that am me too much things on the table…!

Question: I would have gladly only more a telephone, with which I can change the account by function key - thus between UPC and Sipgate.

Can that be done? Is there so a hardware? My Snom can administer up to four SIP accounts, but I want to address the UPC telephone connection also by Voip terminal. Is a thing of the telephone, or the Routers? Or does it need completely which other one?

Mine rout is a Draytek, which is very reliably and therefore I would remain gladly with the mark, if necessary. do I consider a new rout with PBX von Draytek to buy, that would help?

Gaanz thank you for your assistance, and/or. the fact that their into the correct direction points me and loves greetings from Vienna!

ciao, papi