Steam WebAPI Get Players in Server

Is there a way to get a list of steam IDs to players who are on a specific server that you are on? I've been looking at this: https://developer.valvesoftware.com/wiki/Steam_Web_API#GetPlayerSummaries_.28v0002.29

It only gives info based on the steam ID of a player. However, how do I get the IDs of players on a server? Can I do this by an IP search or something?