[rules-users] Hello and my first question

Hello everybody, this is my first post and also my first question to you. I've searched the net for quite some hours now, but don't get any information regarding optionally conditions. I'm using drools to annotate some textobjects and I'm stucking with the following rule: When there are two named entities, one body side and one anatomy in a text (they're defined earlier by a textannotating system, so I'm working on annotated objects) and there is a optionally anatomic side (it contains generally something like "lateral" oder "medial" and so on), then generate me a new annotation. So up to now I'm on this state: Rule "Anatomic Side" when $NE1 : NE(Type.contains("body")) $NE2 : NE(Type.contains("anatomy")) //So here starts the problem [$NE3 : NE(Type.contains("anatomic"))] then ... How can I set a condition as optionally or is there no such way? Thanks everyone to who reads this. Janisch