How to integrate a pre-FTL and a pre-sapient civilization in the same system into your Stellaris empire?

I have a system within my borders that has both a pre-sapient civilization and a pre-FTL civilization. I'd like to integrate both of them into my empire. I know I can uplift the pre-FTL civ and then integrate them after a while, but I worry that if I uplift it, it will settle the pre-sapient life form's planet.

Can I give them sapience and then advance one or the other without them fighting?

You can first colonize the pre-sapients, then uplift them. They will become just another species in your empire. Then you can move to integrating pre-FTL civ. You can infiltrate them, then they will also join your empire right away. Or you can enlighten them. Then they'll became your protectorate which you can integrate later. Or simply conquer them) They'll forget it in a decade or two) No infighting between these two species in either case.

Here is the wiki page about it: https://stellaris.paradoxwikis.com/Pre-FTL_species