The AGATE project proposed the SEPIA system that allows an assistance designer to define assistance systems added in target application. In Interac-tive Learning Environments, such assistance systems are useful to promote the acquisition of knowledge. These assistance systems consist of a set of aLDEAS rules. The articulation between these rules was expressed until now implicitly in the aLDEAS language. Our study of assistance in existing appli-cations shows that the articulation between the rules of assistance can take many forms. We propose in this paper firstly a model of articulation between assistance rules with the five modes of articulation that we have identified. We also present our implementation of this model in the SEPIA system. This model makes explicit and facilitates the definition of articulation between the rules of an assistance system