Bitter Waters by Wen Spencer

Although the human race is unaware of it, there is a war going on between two rival groups of an alien race. The Ontongard infects humans and makes the species one of them, an individual cell in an organism. The pack aliens retain their individual identities while having access to the group memory. The pack wants to kill the Ontongard so they won't destroy the human race. Ukiah Oregon, half alien and half human is the only breeder on the planet and the Ontongard want him to create more of their kind.

Oregon has a son who has been kidnapped. Ukiah, his friend Max, and the pack are doing all in their power to get him back but since the people who kidnapped him are human, they have to be very careful not to let any government official know about Kitt's alien origins. To make matters even worse, the kidnappers are using Ontongard biological weapons, which means that people who don't have any understanding of what they are doing are playing with something that could destroy the world.

Lots of action with a touch of romance.