The first rule of border checks is be truthful. You don't need to volunteer your entire personal history straight away, but do avoid making misleading statements-- like stating that you're traveling for sightseeing or to visit relatives when you're actually conducting business (even if you're sightseeing or visiting relatives in addition to that). It's illegal, and the penalties can be considerable.

Beyond that it's hard to offer guidance without knowing which countries X, Y, and Z are. If you identify them then community members familiar with policies specific to those countries could offer their advice.