how to limit multiple different network client connections

Do you want to limit 50 connections for each or 50 connections for the group of IPs?

you can create as many virtual server with same configuration as you want, with source IP filtering...

• VS1 :
  • destination IP : 1.1.1.1
  • source IP : 210.184.23.35
  • connection limit : 50
  • pool : pool1
• VS2 :
  • destination IP : 1.1.1.1
  • source IP : 2211.34.45.86
  • connection limit : 50
  • pool : pool1
• VS3 :
  • destination IP : 1.1.1.1
  • source IP : 115.53.54.62
  • connection limit : 50
  • pool : pool1

if you want to limit to 50 connections for all of these IPs, you can set the connection limit to the pool instead of the virtual servers.