Best Practice to administer nodes content in BIG-IP LTM

where are they located, networkwise, is the big question here. if you can get them to reach the systems behind the BIG-IP via an internal path then just a forwarding virtual server might be an option.

if they are really located on the outside of the BIG-IP then you can use different ports then the original one. so say 1021, 1121, 1221, 1321, ... for FTP and 11389, 12389, 13389,... for RDP on one IP address.

one jump host behind the BIG-IP, which can be use to transfer to the other might also be an option.