Ground block is really nothing more than a connector that
attached to CATV cable and that permits a 10 AWG ground wire
to be connected. It is even sold in Home Depot with other
CATV cable accessories. Best to put grounding block on cable
outside building and as close to new ground rod as is
possible. Make distance from CATV to ground rod shorter with
minimal bends, etc. Yes that grounded RCA splitter
accomplishes same for human safety and NEC reqirements. But
transistor safety wants that connection to earth ground to be
closer to central earth ground. Also an outside ground block
to ground rod connection makes it easier to keep that ground
wire separate from other non-grounded wires.

Telco provides a "Service's accessible grounding means" in a
box called NID. Their 10 AWG earth ground wire connects their
NID box mounted outside (so that it is accessible) to that
earth ground rod. Some installers want to make that 10 AWG
wire look neat. They will even 'split bolt' attach it to the
breaker box ground wire. However better trained installers
will run their ground wire directly to the top of that ground
rod - as should be the CATV wire ground. All grounds should
run indepenently until they all meet at central earth ground.
This last requirement is not required in code but creates a
more robust and effective earth ground.

As a reminder to others, smart move to have all utilities
located before pounding down the rod.

Mark Wilson wrote:
Thanks to you and "w_tom", I see I may be referring to something different
when I say TV cable ground. After the cable enters the house, it goes to a
standard RCA splitter and it's from there that there is some kind of bleed
off ground wire. It was this ground wire that I was referring to rather
than something coming off a block outside the house. Right now the plan is
to just split bolt the cable ground wire to the EGC just before it heads
outside through the basement wall. I'll will have a look at the outside
block for the TV Cable.
...
The six meters is no problem as the telephone line enters the house right
next to the service panel. However, I'm a little confused by what is meant
by "Service's accessible grounding means". "Accessible" being the key
word, I'm assuming you mean that Telco will ground to the EGC after exists
the service panel, but before it heads outside through the basement wall.