Question: My company has recently acquired another small company. Now, my company has a ERP system that we are using it presently. Also, the acquired company has an ERP system of its own. 

Now I have been given the responsibility of integrating my company's ERP System with the ERP system of the recently acquired company. To do this, I have to map the data between these two processes and see if there are any redundant features. 

However I was told by my friends that there would be lot of problems when I need to sit with both employees of the two companies, given the fact that my company doesn't treat the other company employees that well in terms of credibility. 

So I wanted to know, how do I make sure that there are no hard feelings between both sets of employees and what steps do I take for effective brainstorming sessions among both the teams?

Answer: 
You are in a very interesting situation. I agree with JMort on being assertive and making sure everyone knows you are responsible. 

Now, take in consideration that these two teams will continue to use the final result of your project after it is done (I assume they will not be fired), so you don't want to shut your chances of adoption. Think of the objectives of the project as the goal, but the road needs to set you up for success. 

Be objective and always ask, "why?" I find this question to work very well, even when you already know the answer. Together with, "how would you do it?" takes people from their defensive stand to a more communicative. I often find people complaining without possible alternative solutions, making them more friends of your proposition.

Be open, and open for feedback, but always keep control. **Make sure from the beginning that you say that you will be collaborative, but if there is any tie-breaking you will make that call.** 

As a final point, try to watch for the influencers in both teams, infiltrate them, convince them, and win them. This will make your life much easier.
> 
> how do I make sure that there are no hard feelings
> 
> 
> 

Why? What is the reason to worry about it? You "have been given the responsibility of integrating", not of team building or making peace. Changes typically lead to "hard feelings", it's inevitable. If you blame yourself for them you very likely fail the project. What you need to do in this situation is to identify **negative stakeholders**, identify their needs, and take them into account. That's it.