Translation of interponer

We arrived at my Casa, a private home with an extra place that the family rented. I sat down and they gave me a drink. They explained me that they wanted me to stay at another house for some reason.
A good friend of mine. He works currently in NY but is a Swiss lawyer, excellent and very intelligent. Shall I ask him? OK, sounds great. Maybe we can add his words and expressions (from the law field) as well.
The ship stopped in the middle of several limestone islands and passengers went swimming in the middle of the sea. There were dozens of other boats around us as the area was very touristy.