In my company, when we form the project team we consider integration issues from the very beginning. Along with different functions porfessionals (sales, operation, legal, etc.) we try to determine who from our company will manage the target after closing (future CEO, CFO and others) and involve them in the project starting from DD and site visits. What approach you use in your companies?
When we form the project team, we typically have kind of a matrix structure. On the one hand (top down) we have SteerCo & integration management office (IMO), on the other hand we have all the functions involved (left to right).
Typically we involve people from both acquirer and acquiree in each of these boxes (SteerCo, IMO, for each function,…) throughout the project.