In this paper we introduce NUBIA, a middleware that combines, through business rules, information generated by heterogeneous and autonomous systems. Communication between NUBIA and systems is loosely-coupled and highly compatible, as Web Services and other standards are used. The main component of NUBIA is a rule engine, sensible to temporal knowledge and with integrated functions (e.g. frequencies, percentages). A user friendly interface allows entering, using a script language, customized rules, whose conditions depend on the information sent from the systems. For each rule, settings such as the maximum firing frequency and the activation within a group may be defined. Moreover, NUBIA also supports a rule editor role, which allows a more realistic viewpoint of contextaware rules customization. Finally, automatic rule translation to the user's language and a role-oriented interface facilitate the interaction with NUBIA.