[Zope] remove square brackets in dtml-var

[Joshua Newman]

My <dtml-var mail_group> renders as:  
[mail1@here.com, mail2@there.com]

I am trying to use dtml-var to insert multiple email addresses into a
sendmail form but when I use:

to: <dtml-var mail_group>

I get:

Error Type: SMTPRecipientsRefused
Error Value: {}

Multiple addresses work fine if entered as:

to: mail1@here.com, mail2@there.com

but I get the identical error if I try 

to: [mail1@here.com, mail2@there.com]


Is there an easy way in dtml to shed the '[' and ']' and keep the ','
or do I have to write a python script?

It's not that the python is too terribly hard, I just want to do it
simply, if possible.  
(and it's been a long day and it's hot in chicago w/o a/c)

Thanks again,
joshua