Yes, that is possible. You can set this when configuring your channel in EffectConnect.
Good to know: rounded prices can only be set in a channel that is functioning through the Channel Manager. Not sure if your channel is working through Channel Manager? Then read this article.
To set rounded prices, choose 'channels > channel manager' in the left menu and edit the channel you want to make this change for. Then go to the 'Settings' tab and select 'prices'.
At the bottom of the page, you will find the settings for rounded prices.
Set the rounded prices as desired. Not quite sure what to fill in or choose for a field? View more information by clicking on the icon with the question mark.
Good to know: rounded prices are applied in the very last step of the price calculations. So this can mean that a different price than (for example) the repricer price is also forwarded. This can also result in not reaching the buy-box because your price is just a bit too high.