Fixing concrete posts

[Thecasementkid]

My fence sits on a 1 metre high retaining wall with the timber posts held in place by coach bolts into concrete posts. These badly need replacing and I'd like to use concrete posts this time.
My question is:
Is it possible to drill holes through these posts without them disintegrating? I'd need to drill through the solid section between the rebates.

Any tips/suggestions welcome.

 

[Thermo]

yes you can. drill them slightly off centre so you miss the rebar. drill it slowley and theyll be fine