Before you buy anything additional try all the receivers on the one or
two
split signals. T-adapters and short lengths of coax from the antennas to
the
receivers would be all you need. With the antennas up high and unless
you're
trying to receive weak signals, the split signal might still be strong
enough
for what you want to receive.

If a simple Tee is used ( I assume we are not talking about a 2 way splitter
as used in MATV/CATV)- local oscillator and perhaps synthesizer noise from
one scanner will be impressed directly on the other scanner. Depending on
the freqs monitored- this can be devastating. In addition, loss to each
scanner may be dramatic at those freqs where the jumpers are odd multiples
of electrical 1/4 wavelength.
If the signals are not strong enough in that configuration then keep this
in
mind when you're looking for something to buy: these are receive-only
radios
that do not need to be inductively matched to a transmitter and they do
not
need expensive antennas designed for high power output. A duplexer is not
required.

Frank

I don't think you mean inductively matched- perhaps impedance matched?

Dale W4OP