It is not worthy to name it as "magic" number. How can we call it "magic" while it is not even able to vary. I suggest to rename it "fixed number" or "ID number" or "dead number".
MagicNumber is intended for an EA to recognize his trades (orders, positions, deals). Obviously if you turn away MagicNumber from its original purpose to manage your trades, immediately you encounter difficulties and limitations. For your example you have to manage some data structure internally, for your EA to manage your trades/stops.
From documentation of magic :
If an EA can modify magic number of existing trades (orders, positions, deals), how do you prevent another EA affect your trades including MagicNumber ?