Evaluation dates sharing the same month and year

I currently have this code which displays event dates:

{if statenews_eventstart}{statenews_eventstart format="%d %M"}{/if}{if statenews_eventfinish} - {statenews_eventfinish format="%d %M"}{/if}

I would like to test whether the event start date shares the same month and year as the event finish date, because if it does, I would like to display, e.g. 12-13 July, instead of 12 July - 13 July.

Is this possible? Are there examples of this?

Thank you.