Crystal Reports 11 - can you have a check box as a parameter

I have a report where the user can add a customer number and see all the merchandise they purchased.  What I am looking to do is to also give the user the option to see ALL purchases from customers in the users terroritories.

The following is the record select formula;
(
    if {?Ending Period}<{?Beginning Period} then
    and {region} = "NORTHEAST"          
    and {custcode}={?Customer Code}
    and {date}>={?Beginning Period}
    and {date}<={?Beginning Period}

    else
    and {date}>={?Beginning Period}
    and {date}<={?Ending Period}
    and {custcode}={?Customer Code}
    )

Is there a way to add a check box that if checked then the report will show purchases from all customers?

Thanks,

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