Use a integer array.
After SaveRectHandle, add this:
Custom script: call SaveInteger(udg_RectHash , GetHandleId(r), 1, bj_forLoopAIndex)
You can the load the integer in the enter trigger:
Custom script: set udg_integer = LoadInteger(udg_RectHash , GetHandleId(GetTriggeringRegion()) , 1)
The integer is the index of your integer array.
So IntegerArray[integer] = value for the region