Currently there is not a way to do this. But there are several Ideas that could use your up-vote.
Auto-fill task assignment based on owner of project - https://one.workfront.com/s/idea/0870z0000004Vq6AAE/detail
Connect a Job Rose to Project Owner field - https://one.workfront.com/s/idea/0870z000000H0aFAAS/detail
"Calculated" Task Assignments - https://one.workfront.com/s/idea/0870z000000PSE1AAO/detail
@Kyna Baker - inactive‚ can any of these ideas be combined to increase their individual votes? They're not quite identical, but they all achieve the same end result.
WooHoo!! Just saw that the combined idea has enough votes to be "Under Consideration." Thank you @Kyna Baker - inactive‚ and @Jeremy Flores‚
This will be a huge time saver for us!