Farewell party was held for the unidentified members

In my part-time job, at least 3 members are scheduled to quit the job on February or March in this year. Everybody in my firm knows the fact.
But, during the farewell party, I heard a strange thing.
One of the members said "I couldn't find any shift of 2 members other than the 3 on April duty roster. I suspect that 2 more members are going to retire."

I guess their congested schedules made them retire, if the rumor is true.