I have a data line, to which 4 smaller devices (which each write) and a "master" (which reads from the line) are attached. Only one device should be writing (e. g. connected) at a time to the data line, so I thought to use an IC with a transmission gate in it to leave the line disconnected if the current device is not active (there are other lines which determine the active device, clock and other data). Since the devices are only writing to the wire, I think that the same could be achieved using a multiplexer, but that would require each device to have a separate cable to the multiplexer, which I am trying to avoid. So my question is: Is this the right way to make only one device write to the line? And following up: I have not found any IC containing only transmission gates (using a quick google search), are they sold under a separate name/only included in complexer ICS? I'm quite new to this
EDIT: I think I choose a confusing wording here: So by "devices"/"master" I meant some AND, NOR, Flipflops etc. assembled onto a breadboard. The boxes represent the breadboards ("master" and "devices", to make the drawing simpler I added only two "devices") with gates (shift registers, counters, and-gates etc. but nothing "sophisticated" like Arduinos).
This is how I currently plan to make it: The "master" breadboard (upper middle) either enables "breadboard 1" or the other. If "breadboard 1" is enabled it can set the output (e. g. the "data line") to 1 or 0, while "breadboard 2" has to make it's own output 0 (so that the or-gate takes only the output of "breadboard 1". If "breadboard 2" is enabled, the opposite is the case.
The second option uses switches (or what I intended to be transmission gates). If "breadboard 1" is enabled, S1 is closed and S2 open. The downside is that if neither breadboard is enabled, the line is left floating. But on the other hand, adding new breadboards is easy, and I do not have to use an OR gate. So to rephrase my question: is the second option a good option, and what kind of IC contain this logic (e. g. can you give me example?)