The multilink peripheral is only a feature for nRF52. In SDK 13.0.0 there is a mulitilink example in the ble_peripheral folder: experimental_ble_app_multiperipheral
nRF51 doesn't support multilink peripheral? Do you mean it supports but has no example for nRF51? or It doesn't support multi peripheral?
I need your reply.
No, this example is as a central and connect to up to 8 peripheral,If you want to be a peripheral and being connected with several central ,nRF51 is not support , only nRF52 support as Kristin said.