Is it possible for calls to be routed to an IP address?

Yes, it is. Calls to your virtual phone number can be forwarded to a SIP address. Simply follow these steps:
Setp 1: Log into your account.
Step 2: Navigate on the left side menu to ‘My Numbers’.
Step 3: Click the ‘Settings’ icon on the number which you wish to set/change call forwarding.

Step 4: Under settings when open you can set/change the destination number field and click apply. From this moment on, all incoming calls on your phone number will ring on the phone number you set here.

And make sure to be able to receive calls from us via SIP:

1. Whitelist all following IP addresses on their firewalls for SIP signaling and RTP media traffic:

188.92.57.80/28

213.52.179.224/27

51.163.164.96/27

netmask

/27 = 255.255.255.224

/28 = 255.255.255.240

2. Supported codecs are:
- G.711 aLaw
- G.711 uLaw 20 ms

3. No registration will be used (IP based authentication)