Siebel 7.8 introduces a new business service named "Workflow Admin Service" which offers, among others, this functionality to deploy or activate several workflow processes at a time. This is a new business service that allows you to perform batch import/export, deployment, and activation of multiple workflow processes initiated by way of a search specification. The methods for this business service are: Activate, Delete Deploy, Deploy, Export, and Import.
 
In version 7.7, this functionality is not available.
Note: When you migrate workflow processes using ADM, the workflows are activated automatically. If you use REPIMPEXP or the Siebel Workflow import/export option, you must activate the workflows manually.If you choose not to connect Siebel Tools to your production repository, you must use REPIMPEXP for migration of all your workflow process definitions and later use this Business service for deployment.
Example. Set of W/Fs to be deployed and activated can be chosen using Search specification which is one of the inputs (Input Property: "FlowSearchSpec") to the BS.

The sample code to deploy and active multiple workflows.
 
Multiple Deploy
 if ( MethodName == "DeployTest")
                {
                       var svc = TheApplication().GetService("Workflow Admin Service");
                        var inputs;
                        var outputs;
                        inputs = TheApplication().NewPropertySet();
                        outputs = TheApplication().NewPropertySet();
                        inputs.SetProperty("FlowSearchSpec","Process Name like 'HIG*'");
                        svc.InvokeMethod("Deploy", inputs, outputs);
                        var out = outputs.GetProperty("NumFlowDeployed");
                        return (CancelOperation);
            }
 
Multiple Activate
             if ( MethodName == "ActiveTest")
            {
                        var svc = TheApplication().GetService("Workflow Admin Service");
                        var inputs;
                        var outputs;
                        inputs = TheApplication().NewPropertySet();
                        outputs = TheApplication().NewPropertySet();
                        inputs.SetProperty("FlowSearchSpec","Process Name like 'HIG*'");
                        svc.InvokeMethod("Activate", inputs, outputs);
                        var out = outputs.GetProperty("NumFlowDeployed");
                        return (CancelOperation);
            }