Forum Banning spiders

[محروم.كوم]

Is there a setting or code to prevent the (vB4) forum being spidered by the usual search engines? We have a restricted interest group (a respectable BBC radio station, just in case it sounds dubious!) which can locate the forum via the sites where such groups gather. We don't particularly want our topics picked up by search engines, thus attracting people to the casual content rather than the main shared interest. The forum is hosted by our own website with access via a homepage menu. We want the host website to be spidered, but not the discussions. Possible? __DEFINE_LIKE_SHARE__