Key predistribution in wireless sensor networks has been a challenging field of research. In this paper we discuss a new key predistribution scheme for grid-group deployment of the wireless sensor network. Our scheme makes use of combinatorial design theory for establishing the key-link between different groups. Here we propose a scheme for creating interlinks between the different groups of the sensor network. We use some designated nodes for establishing communicationlinks with other groups. Our scheme ensures better performance with respect to other schemes in existence. This scheme ensures secure keylink between any pair of two groups of the sensor network. Hence, the nodes of any two groups can accomplish communication between them without the help of nodes in other groups.