Mother`s Of The Bride And Groom

My daughter is getting married on May 15th and I need to know is it proper for both mother`s to walk down the aisle together to light the unity candles or is it okay for them to light the candles separately? When my oldest daughter got married the groom`s mother walked down the aisle first and then I walked down after her and we lit the candles separately. I just wanted to know the proper way to do this.