change colspan row-wise while editing table?

[wuuf]

Hello,

I like wym a lot so far. How can I offer the functionality to change between different colspans while editing a table?
I made a custom button to insert a prefilled table, but the rows users add sometimes need one td with colspan=2 and sometimes just two colspans. Can I enhance the little arrows/cross-GUI in some way?

Thanks, wuuf