A typical grid application requires several processors for execution that may not be fulfilled by single cluster at times. Co-allocation is the concept of aggregating computing resources from more than one cluster to facilitate application execution. It poses great difficulty in implementing as these resources are distributed and managed locally. In this paper, we propose a metascheduling framework that achieves co-allocation using the concept of virtualization. Our approach differs from earlier ones as we create virtual machines to meet the requirements of application thereby utilizing the resources to the fullest possible extent while preserving their autonomy. We used Deviation Based Resource Scheduling algorithm to initiate SLA negotiation with other resources for participating in resource co-allocation. It also supports SLA monitoring and enforcement. Our preliminary results show that this approach achieves greater throughput against conventional scheduling.