Can you work ferrets from two different sources or might they start fighting?
Personally I wouldn’t work my ferrets with others that they don’t know.
I’ve tried it in the past but always found that my ferrets didn’t work as well as usual and tended to spend too much time following one another around rather than concentrate on hunting.
If I were you, and plan to work two different lots together, then I would be minded to house them together first before putting them to work – this way they will be used to one another and be more focused of the job in hand.
They are unlikely to fight, but I just find it an unwanted hindrance.