"Tea for three at three"

I am making it a point to check the Library of Congress website periodically to be sure I don't miss any new additions to their collection of tea-related photos. This week, I came across one I'd not seen before, a 1931 image titled "Tea for three at three aboard the Detroit Mackinac Chicago boat." Now I wish the photographer hadn't chopped the shoes off the lady at far left, but I sure enjoyed seeing all these great clothes as well as the shoes on ladies number two and three.
When I see a vintage photo like this, I am always tempted to make up a story to go along with it. Who were these ladies, and why were they taking tea together on this boat? And who is the little boy standing behind the woman seated at right? Her son? Her nephew? Her charge?

And more important, what brand of tea were they sipping? I love seeing vintage photos of women together, and I hope you do as well!