Yes, you can use a regex to get the words from file1 that you're going to search for and insert into file2. There are many different ways it could be written, but here's one example:

my $str = q|{RP}makaravilYakkin Sabarimala ayyappanu cArZwwAnulYlYa wi
+ruviwAMkUrZ rAjAvAyirunna SrI ciwwirawirunnAlYZ bAlarAmavarZmma natak
+k vacca  420 kilogrAM wUkkamulYlYa wafkayafki{/RP}{MCL} sUkRikkunnaw 
+I kRewrawwilAN.{/MCL}|;

while ($str =~ m[
   {(\w+)}         # a word within {}, capture it
   \W*             # maybe non-word chars
   (\w+)           # first word after tag, capture it
   [^{]+           # anything but a {, up to...
   \W              # a non-word character
   (\w+)           # last word before tag, capture it
   \W*             # maybe non-word chars
   {/\1}           # ending tag matching captured one above
]xg){
    print "$1 $2 $3\n";   # print captured values
}
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