[Zope] bobobase_mod_time of other objects

Hello- if I want to use bobobase_modification_time to tell me when another object has been updated, how would I format it? For instance, in a index_html DTML document I want to list the last update of other objects in the same folder (other DTML documents and methods). I can't get bobobase to reference _other_ objects. Is this possible? -andy