Well, yes an no.
If you have 1 omnidirectional
transmit antenna, and two receive antennas 10 foot
radius away, but not too close to each other, then
the presence or abseince of either of the receive
antennas does not change the receive power to either
of the antennas.
But, each receive antenna
has an "effective aperture", so much of the signal
sent at that aperture will go into the antenna.
So if you place one antenna 10 feet away, and another
antenna 15 feet away on the same azimuth/elevation,
then the first antenna does suck up a lot of the
power at that particular solid angle, and only some
of the power sneaks by to the second farther antenna.
So in that particular case, the power to the 2nd
antenna is reduced somewhat. The first antenna either
absorbs, or reflects the power at that solid angle.
An obvious example would be a dish reflector
antenna as the 1st antenna. Not much is going to
get by the reflector dish to the 2nd antenna if
they are on the same radial.