Can You Use A Different Merchant Account In Quickbooks?

We currently use three merchant accounts at our business: one for Quickbooks, one for the boss’ telephone orders, and one for our e-commerce website.
We are looking at consolidating to one, but from what I’ve heard, you can only use Intuits merchant account in Quickbooks. Is that true? or can you change the information and accept credit cards through a different company?
Thanks!