Sounds like something spies used to do at Checkpoint Charlie, as they are not connected (4,6)
I believe the answer is:
free agents
'they are not connected' is the definition.
'sounds like something spies used to do at checkpoint charlie' is the wordplay.
I cannot really see how this works, but
'spies' could be 'agents' (I've seen this before) and 'agents' is located in the answer.
The remaining letters 'free' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'as' is the link.
Can you help me to learn more?
(Other definitions for free agents that I've seen before include "uncommitted participants" , "people lacking commitment" .)