Umbrella
Using a hat, four persons with a cross make an umbrella. The hat is big enough to be an umbrella for all four people, so it makes sense. All four of them are religious missionaries, so that's why they're holding the cross under the "umbrella."
さん
かさ
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You know the Spanish phrase "Mi casa (かさ) es su casa"? Well, this is kind of like that, but only with a hat. And that hat is also an umbrella. Mi casa es yours too, because it's an umbrella and also a hat. This makes sense, trust me.