^^^
Use old trick by saving contact with number 3 only,
Dial first number, after getting connected . press home and select 2nd contact. 1st caller will be on hold automatically.
After 2nd call get connected , again press home and from contacts select contact with number 3 and try dialing from there.
As soon as you press on number 3 , you get connected to con call.
Works on many devices .
Sent from my Falcon_CDMA (Moto G)