No.
RSLogix 5000 version 15 allows creation of I/O connections to 1756-series network bridges (1756-ENBT and 1756-CNB(R)) on EtherNet/IP and unscheduled ControlNet networks while the controller is in Run mode.
It does not support creation of those connections in Run mode to any other platform or device, including FLEX, POINT, or 1771 I/O.
Do you have a ControlNet installation that allows you to connect adapters without disconnecting the trunk cable ?