Probably the best way to do it would be a custom VBA function switching between values - That would give you the most amount of control, but you could do it with nested IF()
statements too:
=IF(A1<1000,CEILING(A1,10),IF(A1<100000,CEILING(A1,100),IF(A1<1000000,CEILING(A1,1000),IF(A1<1000000000,CEILING(A1,100000),CEILING(A1,1000000)))))
Hope that helps!!