Stetting up FTP and SFTP adapters for the same interface

Experts-

I have a situation in which client has a requirement to setup both FTP and SFTP adapters (from adapetive adapters) for the same interface. They want to have a copy of file locally and also want a file to be sent out securly using SFTP. In my interface which was previously developed they have used one business system and added FTP and SFTP to the same. If try to add new Receiver Agreement it will say that the object already exists as the Interface Mapping is same.

Please send me any suggestions which would resolve my problem