This depends on what connection behavior you would like to achieve. The hollow core slab manufacturer will typically have standard connection details or assist you with the connection design. Usually beams/columns are designed such that the prefabricated hollow core slabs can be lifted into place. Therefore, usually there are corbels or ledges for the slabs to sit on.
To get an idea, Hollow Core Concrete Pty Ltd (Australia) has Hollow Core Slab Technical Sheets on their website showing some typical connection details.
For example, I have taken the detail for an internal beam to hollow core connection from their website: 
It is worth discussing the design with the hollow core manufacturer to get an expert opinion. I always recommend using the experts instead of trying to re-invent something.
As @Wasabi pointed out I didn't address the situation you mention in the comments with the slab and beam having the same depth. This is a non-standard detail with regards to hollow core slabs. As I mentioned earlier, hollow core slabs are typically used in pre-cast construction. If you are casting integral beams, this removes much of the advantage of using hollow core slabs in the first place. You could just cast a voided slab in-situ for example.
If you need to use hollow core slabs in this situation there are potentially a few ways this could be achieved, for example: breaking out part of the hollow-core slab, adding the additional reinforcement then casting new concrete to fill the space; or using a concrete half-joint detail. The manufacturer may also be able to incorporate this beam into the design of the slab. Any of these non-standard connections would depend on your loading and other design and construction constraints and would likely need to be designed in collaboration with the hollow core slab manufacturer.
If you are willing to use steel-concrete composite construction you could use a typical slimfloor approach:

The space around the steel beam would be filled with concrete, and if you wanted to get very clever you could even add rebar in this space.