Demuxer is corrupting object meta of secondary detector

I am working on Automatic number plate recognition in which first I have to detect number plates as the primary detector and then detect and recognize characters in the plate as the secondary detector.

There could be multiple plates in the frame therefore characters can belong to multiple number plates.
So while processing object meta I should have information about which character belongs to which numbers plate.

I was talking about StackOverflow so that I could reach more people like you.