Dear all

I have a hopefully trivial question that I can't get my head around right now. My data set is clustered and consists of neighborhoods, households, and household members:

Code:
clear
input neighID hhID hhmemberID
1 1 1
1 1 2
1 2 1
1 2 2
1 2 3
2 1 1
2 1 2
2 1 3
2 2 1
2 3 1
end
I.e. hhmemberID is only unique within hhID, hhID is only unique within neighID. How do I get hhID to be unique overall? I.e., like this:

Code:
clear
input neighID hhID hhmemberID
1 1 1
1 1 2
1 2 1
1 2 2
1 2 3
2 3 1
2 3 2
2 3 3
2 4 1
2 5 1
end
One option would be to convert neighID and hhID to strings and to concatenate them (or whatever the correct term for banging them into one string variable is), but I wonder whether there is a less haphazard option?

Cheers
Go