How to conditionally range through posts for multiple taxonomy terms?

I am using taxonomies and several taxonomy terms. How do I conditionally range for all the posts that either have taxonomyterm1 or taxonomyterm2 or taxonomyterm3 ?

i.e. The final range list should display all posts if it has either of the above taxonomyterms.

{{ range where (where site.RegularPages "Type" "posts") "Params.tags" "intersect" (slice "tag-a" "tag-b" "tag-c") }}
  <h2><a href="{{ .RelPermalink }}">{{ .Title }}</a></h2>
{{ end }}