WINS for Multiple Domains

Is it possible to have One Primary/Secondary WINS server for multiple domains? I have been asked to reduce the amount of WINS servers that we have on our network. We currently have 3 separate domains, each with a PDC and BDC. Each domain is configured for its own WINS server, but I would like to consolidate them to one primary box and one secondary box. Is this possible, or do you have to have a separate Primary/Secondary WINS servers for each domain? The primary/secondary servers are located in different physical locations. Would this be a problem too?