Bitrix24 telephony integration

Hello All, We need to integrate Vonage and Callcentric SIP with our Bitrix24 installation for calling to USA. This will be used with a 10 PC user system for a call center. Other requirements with same: - SIP set up in Bitrix24 - Setting user right for 10 users with extendable option to more users. - Setting up rules for call forwarding, call picking, call sharing etc. - Complete testing of system on each user account. People who have already worked with Bitrix24 or any other telephony services must contact with timeframe and price. Questions welcome.