Use an inverted character class: [^;]* instead of .*? - then

$_ = ';A-B;C-D;E-F;G-H;J-K;L-M;N-P;R-S;T-W;Y-Z;';
print $1, "\n" if /;([^;]*W[^;]*);/;
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yields the desired result.
You don't have to escape the semicolon, since it is no meta-character.

See perlre and "Bracketed Character Classes" in perlrecharclass.