introducing a new baby

I have had my one baby piggy for about 2 weeks and today I got another baby to bond them. I had floor time with them first and everything seemed good so I put them in the pen together. they do alright but the older one will shove the new one around and there is minor teeth chattering. They also are squeeking alot. I have never bonded pigs before so I am scared they will hurt eachother. How long do pigs usually take to bond with eachother and do you think I should seperate them? Thanks