I often use multiple hidden bricks for various events.
Unfortunately I think the maximum delay for an event is 30000, or 30 seconds, so you'll need two delays
[30000] onWhatever -- self -- fireRelayUp
Brick on top of that
[30000] onRelay -- player -- whatever
I think the player that triggers onWhatever will still be affected by the second brick. Maybe you've already tried this and I'm useless, but this is the kind of thing I'd try first.
I'm a doofus; if onWhatever is not onRelay, you could put that on one brick, and make it self -- fireRelay instead of Up. This is only a problem if the first event is started with onRelay, because then it becomes a loop
uh oh I've lost the ability to make events without looking at the game