I am not quite understanding. Is this a workflow and if so is it in designer or K2 Studio or is this a form.

By dynamic string I assume that means a user is typing something in and you want to find a group. Are you calling a smart object and if so which one.

A little more information might help to understand what is being asked.

Thanks so much for your reply,

This is a workflow built in k2 studio. By dynamic string i mean something like "Contant string - " + Worflow Item Column value. Lets say "Worflow Item Column value" has two values 01 and 02 as a dropdown colum . if 01 is selected on creating the sharepoint item, it should search for group name "Constant string - 01" . And if 02 is selected it should search for "Constant string - 02" .  Both the groups already exist in the site.

I have not set this up in my environment to replicate this but I have an alternate solution that might work.

It seems you are setting line item or permissions based on the type of record. If record =1 then assign to group1 and record=2 assign to group2.

Rather than trying to build a SharePoint group from a dynamic string. Divide your workflow action into two actions. Action1 will assign permissions to group 1 and Action2 would assign permissions to group2. You would use a line rule record=1 to send to Action1 and record=2 send to action 2.

Does this seem to apply to your situation?

Yes, This is exaclty what I have implemented now. But we have almost 10 such nodes and more to be added in the future, which makes the Workflow very large. There is no way this could be implemented dynamically?