I'm the IT Director (CIO) for a team of approximately 40 people. My organization prides itself on treating employees well, and many of my team members have been here for 10 years or more, progressing through different roles as openings arise. It's a tight-knit group that works very well together. I have been in this position for only 18 months, having been hired from outside; the previous (very beloved) IT Director is now COO and has been with the firm for 25 years.
I have 7 managers and one Assistant Director on my team. Since I arrived, one manager has left to pursue a large promotion at another firm (Director-level). A few months later, my Assistant Director, who has had a long-term plan to retire to Florida, announced that she would be moving later this year. Last week, another manager announced that he was leaving.
I believe that it's important to reassure my staff that these events aren't connected, and that I'm not trying to get rid of the old management team in order to install my own. How can I do this most effectively without seeming to be defensive?
EDIT: As a followup, I was able to promote from within for this position. Thanks to everyone for the suggestions.