Dual Intentions In A Qurbani Animal

Yes, a person can make dual intentions for Qurbani when it is a big animal, such as a camel or cow etc. In other words, he could purchase one share in a cow for his Waajib Qurbani and purchase another share in the same cow for his Sadaqah Qurbani. 

Such dual intentions however, will not suffice on a small animal (e.g. goat, sheep), because each these small animals constitute only one share wherein one can make an intention of either a Waajib Qurbani or a Sadaqah Qurbani; not both.