Issues related to multiplexed analog signals
What you are asking for is possible, but at those speeds you won't get much signal to noise ratio.  Of course it would help to know what your upper frequency of interest in the sampled signals is, and what resolution and accuracy you want to measure them with.  Longer transmission distance will degrade the signal more.

All these reasons and more is why things are not done this way anymore.  The phone system, for example, has long ago converted to digital.

Your question is a imagines solution instead of the real problem.  Tell us what you really want to accomplish, not how you think it should be accomplished.

A deliberate gap between adjacent signals is just a waste of settling time.  Each signal should start as soon as possible within its time slot.  One problem with these systems is syncronizing the sender and receiver.  One way is to send a sync pulse each frame.  In old TV, this was a blip more negative than any valid signal.  You could use that to sync a phase locked loop, which would then generate the clock to find the individual time slices.

Once you get all this working and discover all the various sources of error, you'll understand why these things are done digitally now.