String double stops and chords

What is the best way to write a double stop or chord for a string instrument such as a violin? For example, on the violin composers may call for a four note spread chord using the open G and D strings, B on the A string and G on the E string. The only way I've found to write this is to put the G, D and B as grace notes before the upper G. The usual notation is simply to write all four note heads on a single stem. Is there a way to do this?