This paper proposes an innovative mechanism to achieve flexible access control during co-ordinated resource sharing in enterprise grid environment. The solution proposes an elegant mechanism that is very easy to implement and highly flexible at runtime. The mechanism proposes a new model for users, resources and their relationships which define co-ordination and access control. The solution targets to satisfy the demands usually found in enterprise environments with respect to controlled sharing of resources. The proposal envisions its applications into grids designed particularly for enterprises.