# I assume you are using 2 different pdls, not rows of the same pdl as you mentioned in your post
# If it's just one pdl, 'dog' it
my $value = pdl [ 1, 20, 60, 3, 900, 34, 93, 5, 12, 24, 16, 200 ];
my $mask =  pdl [ 1, 1,  0,  0, 0,   1,  1,  0, 0,  0,  1,  1 ];

# get the indices of $mask that are 0
my $indices = which $mask == 0;

# detect lower and upper edges of sequential regions of indices
my $lower_edges = $indices - 1 != $indices->rotate(1);
my $upper_edges = $lower_edges->rotate(-1);
# also:
# my $upper_edges = $indices + 1 != $indices->rotate(-1)

# now slice and dice up your piddles knowing the regions you want.