[Zope] "Dynamic" dtml-with

Is there a syntax I can use to include another folder in my namespace, when I wont know which folder until runtime? For example, if I have similarly-named preferences for different customers in folders CUST1 and CUST2, I would like to at run-time be able to do something similar to: <dtml-with "CurrentCustomerString"> to get the correct customer folder in my namespace. Thanks in advance for any suggestions.