Please help with AWK - MATCH function

Hi,
In the example below I am matching on SURNAME, some characters and then a comma. However, because in the line of text SURNAME2 is often before SURNAME (but not always), SURNAME2 is getting picked up twice !!! How can I change the match for SURNAME so that it still does what I want but doesn't include SURNAME2 ??

BEGIN { }
{
surname = match($0, /SURNAME[^,]*,/);
if (surname)
output = output substr($0, RSTART, RLENGTH-1);

surname2 = match($0, /SURNAME2[^,]*,/);
if (surname2)
output = output " , " substr($0, RSTART, LENGTH-1);

Many thanks for your help.

If you extract the data for SURNAME2 first, change the string SURNAME2 to "xxxxxxxx" you will be able to search $0 for SURNAME????? successfully