Kit 1 programming remote to operate 2 seperate units

I have 2 Kit1 units with 4 remotes, I have set them up for timed mode, A & B operate Kit1 A relays C & D operate Kit1 B relays, it works except if you activate A or B then activate C or D before the others timer expires it shuts them off, is there a way to resolve this?

Sorry it is anticipated behaviour & limitation, since (any unprogrammed buttons will by default turn off timer mode immediately).

It can be bypassed by set our receiver in UTM (uninterrupted timer mode), but it has one major problem, that you can’t operate any relay (receiver stops responding to remotes) when at least one relay is in timer mode and counting down.