Everything stock is most likely a little hopeless but we can do a lot better with Proc Fairings using the enum for what kind of fairing it is:

https://github.com/KSP-RO/ProceduralFairings/blob/ac26a05dbe027d466e22d214d958cbac2f14acd5/Source/ProceduralFairings/FairingBase.cs#L20-L23

VesselState can maintain a list of Proc Fairing payload fairings and then when the fairing conditions are met the stage code can trigger them all if the set isn't empty. That likely means that Proc Fairings could be left disabled out of the KSP staging display and they'd just fire when conditions were met correctly.

For stock it might be possible to add yet another UI element to do something like fire every fairing in KSP stage X (where X might conventionally be zero) when conditions are met.

the ability to detect a proc payload fairing vs. interstage fairing was added, although not the ultimate goal of having the payload fairings not even in the staging sequence.