there might be some way, but also this depends on how often you perform the same routine in one set/evening..
If you 'solely' perform it 4 times (as you mentioned you had to keep track of 4 cards in another solution) the following option is doable.
Use 4 dif. cards, and those cards are already removed from all the decks you use/switch in.
Then, from your normal deck, force any of those 4 cards, it's easy the first time, as you have 4 to start off with..after the selection is signed, let them keep it, and as your switch in the next deck, it doesn't contain that card, everything is OK.
Next time -at another board-, force one of the 3 cards you have ready..aso.
Also, this is good practise re classicforcing cards.. :)
Unless you're a real purist, round the top left and bottom right corner of these 4 face down cards in your normal deck a bit more, solely so you can always *cull* them by a corner riffle with the left thumb to locate them and get-ready for a force..it doesn't matter which one of the 4 you use, first 4, then 3, then 2 and then the last one..always ready to locate *a* card you want to force..
Maybe it sounds a bit too complicated, but it is a solution (though not THE best, but it works), unless you do your set more then 4 to 6 times and have to remove too many cards from your decks..