"Copy trading" or "Order broadcasting" or "Order mirroring" is the way of reflecting orders from a "master trader" into multiple "follower" accounts. This is useful if your friends want to just follow your trades exactly.
QuantIndia (QI for short) has introduced copy trading facility with full controls. The master-trader can specify which orders should be mirrored into which accounts. Orders get executed typically within 1-3 seconds.
All inputs are specified in excel and uploaded into the system. Runtime update to the parameters is supported.