{show urls="(&|\?)email=[a-z0-9+_.-]+@[a-z0-9]" urls_regex="true"}
{show urls="[&\?]email=[a-z0-9+_.-]+@[a-z0-9].*?some-condition=for-field-1" urls_regex="true"}
... code for field 1 ...
{/show}
{show urls="[&\?]email=[a-z0-9+_.-]+@[a-z0-9].*?some-other-condition=for-field-2" urls_regex="true"}
... code for field 2 ...
{/show}