This principle is stated explicitly in Revelation 17:9-10, ESV: “. . . the seven heads are seven mountains, on which the woman is seated, they are also seven kings. . . .” Revelation 17 can be totally bewildering if each symbol is treated as a unique entity. But the chapter simplifies quite a bit when you realize that the same entity in reality can be represented by more than one symbol in Revelation. For example, Jesus is represented in Revelation as a son of man, a Lamb, as a male child, and as simply Jesus Christ. The end-time people of God are represented by the woman of Revelation 12, the 144,000, the great multitude, the saints, and the remnant.

This principle can be seen at work in the first three verses of Revelation 17. In 17:1 a prostitute sits on many waters. In 17:2 she commits adultery with the kings of the earth. In 17:3 a woman sits on a beast. That woman is called both prostitute and Babylon in verse 5. So it is clear that the prostitute of verses 1 and 2 is the same entity as the woman of verse 3 and Babylon; a worldwide unity of religion in opposition to God and His people. Similarly, the waters of verse 1 (defined as the political powers of the world in verse 15), the kings of the earth in verse 2, and the beast of verse 3 all represent the same entity: The secular, political powers of the world who support Babylon for a time but then destroy her at the End (17:16). So I think I know that multiple symbols in Revelation can represent a single entity in real life. The enemies of God at the End are not multiple in the chapter, they are two in number (more on this later), Babylon and the beast.