Sure. One precut cable for every upstream coupled cable plus one full-length cable for any downstream cable. That would be one way.
Depending on the situation, that could be simple or a real pain.
My S&S bike does not use shifter cable connectors, the shift cables are full length outer housing and they are easy to disconnect from the rear half of the frame. I carry a pre-cut to length single shift cable for my Rohloff hub. The Rohloff uses two cables, I was careful to make sure both shift cables are same length when I built the bike, so only one spare is needed. The frame came with a cable splitter for rear brake, but I chose not to use it when I built it. Thus, for me, having this coupled bike is the same as a non-coupled bike when it comes to cables.
But my Ritchey Breakaway bike, I bought it as a complete bike, thus I did not have an opportunity to measure cables. I would have to remove the rear brake cable to measure a new one. And I do not know if both of my shifter cables are the same length (lever to coupler length), thus I would have to remove both just to find out if I need one or two spares. If I take this bike on a trip, I am bringing full length cables that would not use the coupler if I have to replace one. And before someone says, why bother, breakage is rare, this bike uses Campy cables and a lot of bike shops only carry Shimano/Sram cables, so there is a reason to carry the spares if I travel with this bike.
Both of my coupled bikes are solo bikes, not tandems. If the OP can be assured that a tandem length cable is long enough, he could replace a cable and not use the couplers in the process. Then once home, could cut some cables to re-install the couplers.
I do not know if all tandem cables are long enough, I use two tandem length cables for shifting my folding bike, the cable runs on the folder are quite convoluted due to the folding mechanism. I recall on one occasion that my tandem length cable was too short to be installed on my folder, I needed a different longer tandem cable.