Presale Question : Affiliation only on a specific category

Hello,

For a client I mine, I am benchmarking, the affiliation solutions available.
Yours looks great so far. Other solutions seems overly complicated.

However, I have a special requirement :
The online store holds different products.
There is a special category of products (gift vouchers), and only these products are eligible to affiliation.

Is it possible to make sure that buying other products will not trigger a payout ?

Regards,