Compare two files using awk or sed, add values in a column if their previous fields are same

Hi All,

I have two files

file1:

abc,def,ghi,5,jkl,mno
pqr,stu,ghi,10,vwx,xyz
cba,ust,ihg,4,cdu,oqw

file2:

ravi,def,kishore
ramu,ust,krishna
joseph,stu,mike

I need two output files as follows

In my above example, each row in file1 has 6 fields and each row in file2 has 3 fields. I should compare field2 in both the files. If field2 is same in both the files then i should get the third field in file2 as the last field in file1.

output:

abc,def,ghi,5,jkl,mno,kishore
pqr,stu,ghi,10,vwx,xyz,mike
cba,ust,ihg,4,cdu,oqw,krishna

Also, If field3 in file1 is same as field3 in the next line then the field4 should add upto field4 in the next line and i should get a unique output as follows

ouput:

abc,def,ghi,15,jkl,mno
cba,ust,ihg,4,cdu,oqw

can somebody please help me with this as i require it pretty urgently. I am using sun solaris. If we can get the output using sed or awk that would be great. Any other way is also appreciated.

Thanks in advance..........

Double post, closing thread. Continued here