How to setup an allocation request with multiple criteria's in it?

I have a 20 chartfield combinations whose sum of posted total amount is say $2000 and each chartfield combination has different posted amount(i.e $20,$30 and so on). I have another set of chartfield combinations whose sum of posted total amount is $500. I need to set up a new allocation request whose line amount would be as (20/2000)=0.01 *500 =5. Can someone help me in setting up this kind of request.

    

location	dept	account	string amount		Desired output
Loc1	dept1	acct1	20		5
Loc1	dept1	acct1	30		7.5
Loc1	dept2	acct1	5		1.25
Loc1	dept3	acct1	10		2.5
Loc1	dept4	acct1	0		0
Loc2	dept5	acct1	200		50
Loc3	dept6	acct1	190		47.5
Loc4	dept7	acct1	60		15
Loc5	dept8	acct1