formatting problem in table command

[Tom Gumpel]

I am trying to build a table, see code.
Note that the CI is not formatting correctly because of negative values adding a column. How can I add a column to only the non-negative values, or any other way to reformat this table?

Many thanks.

table () (command result),                               ///
    command(_r_b _r_se _r_z _r_p _r_ci                   ///
    : regress var1 var2 var3 var4 var5)                  ///
    nformat (%5.2f _r_b _r_se _r_z _r_p _r_ci     )      ///
    nformat (%5.4f _r_p)                                 ///
    sformat ("[%s]" _r_ci)                               ///
    cidelimiter(,)