For starters, you would need a field that is a string type (text) not numerical. You can then populate it by concatenating a dash into it at the appropriate places.
For example, a simplistic way would be to shred 6411 10 6411 12 down to it's 4 pieces and place each piece in it's own field, say field A, B, C, D. For example, A would contain 6411, B 10, etc. Then create a text field for your final result, we'll call it field E. Then run Field Calculator on field E, with the VB script expression: & "-" & & " " & & "-" & .
There are probably even easier/more elegant ways to do this with Python.
One catch will be whether all your data is laid out in the same sequence; if it varies it may take some data cleanup or additional code to get it sorted out before concatenating.
Chris Donohue, GISP