Shell Programming and Scripting

I've got two large csv text table files with different number of columns each.
I have to compare them based on first two columns and create resulting file
that would in case of matched first two columns include all values from first one and all values (except first two colums) from second one. I searched forums and as well google - and was unable to find solution for that issue.

file1 example:

123 234 678 974 943
345 55 567 21 357
456 732 583 61 75

file2 example:

123 234 582 699 23 11 935
22 467 215 376 87 54
456 732 32 14

Expected resulting file:

123 234 678 974 943 582 699 23 11 935
456 732 583 61 75 32 14

just to compare I've been trying to use following code in awk, that I found in google:

awk 'NR==FNR {++a[$1,$2];next} a[$1,$2]' file1 file2 > file3

but I am stuck with understanding how to add data from second file for matched line...