Lync Hybrid, Online already set up

[CAWJames]

Hi all, me again!

 

We currently use Lync online across the college, and it works very well for video conferencing and general "at-desk collaboration".

 

I now want to add an on-prem server so I can hook our PBX into it, and then move some users to the on-prem for phone support.

 

Has anyone done this, all the guides and posts I have seen work from an on-prem then add online scenario.

 

Do I just:

 

Setup ADFS on top of DirSync(we already DirSync but dont federate).

Create an on-prem mirroring the domains we already have in online.

Set up a Hybrid.

 

That seems too easy, as the DNS is giving me a headache. If we already have meet/admin etc setup for online, what happens when the on-prem expects to be contacted via this too?

 

Any O365 experts around?

 

Thanks

 

James