vba - Regex to Replace text without using lookbehind -

i have text file several items (blocks of text) following:

sample item_id sample_id_0000028 blah blah abcd <--- not remove blah blah blah blah blah blah sample_end   sample item_id sample_id_0000033 other text more text abcd <--- remove more text sample_end  sample item_id sample_id_00041 abcd <--- not remove blah blah blah blah sample_end 

i want replace/remove instance of abcd occurs in item id sample_id_0000033. challenge there other instances of abcd in file want leave alone. also, number of lines between item_id , abcd varies item item, , it's possible abcd not found in specified item.

i must manipulate file via vbscript in vba. figured use regex this, vba not support regular expressions lookbehind. there pattern can used accomplish negative lookahead or simpler that?

i execute regex on string defined textfile.readall, textfile textstream.

you can use this:

pattern: (item_id sample_id_0000033\d(?:[^s]|s(?!=ample_end))+?)abcd replace: $1 

or better, this:

pattern: (item_id sample_id_0000033\d(?:[^\r]+\r\n)+?)abcd replace: $1 

or shorter acheong87 example:

pattern: (sample_id_0000033\d(?:[^\r]+\r\n)+?)abcd replace: $1