I believe \orelse might be what you want. It works with most \if... macros, and it avoids nesting of \doifelse constructs. Here's an example, which I use in conditionally removing preceding punctuation if any other keys are defined before a specific one in an assignment:
```
% If any of the preceding keys was specified, then replace any preceding punctuation with a space
% and typeset the number with its CSL abbreviation, followed by a comma
\ifdefined\btxsbllocvol
\removeunwantedspaces\removepunctuation\btxspace
\orelse\ifdefined\btxsbllocno
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocpt
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocp
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocn
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocfig
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocop
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocbk
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocep
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocchap
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocv
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocfol
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocfrag
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocpl
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsblloccol
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocl
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocsv
\removeunwantedspaces\removepunctuation\btxspace
\fi
\orelse\ifdefined\btxsbllocsec
\removeunwantedspaces\removepunctuation\btxspace
\fi
\fi
```
Joey