Inter-grid is a composition of small interconnected grid domains; each has its own local broker. The main challenge is to devise appropriate job scheduling policies that can satisfy goals such as global load balancing together with maintaining the local policies of the different domains. Existing inter-grid methodologies are based on either centralised meta-scheduling or decentralised scheduling which carried is out by local brokers, but without proper coordination. Both are suitable interconnecting grid domains, but breaks down when the number of domains become large. Earlier we proposed Slick, a scalable resource discovery and job scheduling technique for broker based interconnected grid domains, where inter-grid scheduling decisions are handled by gateway schedulers installed on the local brokers. This paper presents a decentralised scheduling technique for the Slick architecture, where cross-grid scheduling decisions are made using a fuzzy-logic based algorithm. The proposed technique is tested through simulating its implementation on 512 interconnected Condor pools. Compared to existing techniques, our results show that the proposed technique is better at maintaining the overall throughput and load balancing with increasing number of interconnected grids.