WWI photographic postcard of a group of Y.M.C.A workers

Greyscale Real photo postcard (R.P.P.C.) showing a group of female Y.M.C.A. workers in uniform.
They are mostly wearing light coloured uniforms with large white collars trimmed with lace and armbands with the Y.M.C.A. logo (an inverted triangle). They all have white veils tied in a variety of ways. Their dresses are long and have belts and buttons down the front. There is some variation with a couple of dresses having a crossover front and other women having a sash, perhaps indicating seniority.
The photo is taken inside a building with light coloured walls and ceiling and there is an indoor palm tree in the background.