Where is the text? If you attach the text, then I can help you write the conclusion.
The simple subject would definitely be "Many" because these "Many" are the people do something, which leads us to the predicate. The simple predicate would be "were sent" or "sent" because that is what the "Many" were doing (technically they were forced).
Answer:
It is a transition word.
Explanation:
"Meanwhile" is a transitioning word. Hope that helps.