data - sort by numbers

I have a table and one column has the following order:
3
3.1
3.1.1
3.1.2
3.2
3.2.1
3.2.2
4
etc
but new rows will be added so each number may have different ranges ie. 3.1.1 to 3.1.15.

people will go going in and sorting by different columns. but once they sort on the number columns i'd like the format to be the same as above. is there a way to do this?

it sorts like this:
3.1
3.2
3.01.02
3.01.03


But needs to be:
3.1
3.01.02
3.01.03
3.2