several clients one payment

[Laboratorio Verónica Gómez]

I guess this isn't a frequent situation, but is there any way to match 
one single check payment against several invoices from more than one 
client at a time?
I've configured different clients with separate invoices because they 
have different billing terms, but they usually pay through an 
'intermediate' client  with just one check for all of them. The FIFO 
order for paying several invoices is not useful for me because the 
differences in billing terms (some invoices are paid sooner than 
others). Any help?
Sorry if my English isn't correct (it's not my native language)
Verónica Gómez