2 fields with same value

Hi everybody,

I am trying to have one block with 2 attributes with the same value. I am wondering if it is possible to have 2 fields witch the value is the same as an attribute block. I mean, I need to have the same number in each end of one line, and if I modify one of them, the other one update automatically.

Is it possible?

(I think that some similar can be done with fields and objects in Autocad).