"five friends have access to a chat room . It is possible to determine who is chatting if the following information is konwn?

"five friends have access to a chat room . It is possible to determine who is chatting if the following information is konwn? Either kevin or Heather or both are chatting. Either Randy or Vijay but not both are chatting . If Abby is chatting so is Randy . Vijay and Kevin are either both chatting or neither is . If Heather is chatting then so are Abby and Kevin. Explain your reasoning?