I'd just be lazy and use a flip-flop.

#!/usr/bin/perl -n

if(/RECORD\s+"(?:ABC|XYZ)"/ ... /END_VIEW/) {
    s/^\s*field\s+\K"region"/"LOCATION"/i;
    s/^\s*field\s+\K"rubbish"/"TRASH"/i;
} 
print;
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Having the structure inline, I'd just split then into @lines and say for(@lines) { ... }

More matching pairs can be introduced with nested if-blocks of the same form - if (m{...} ... m{...}) { ... }