If possible, select two SAW filters that not is overlapping.
A SAW filter have often rather low impedance outside of its pass band. Paralleling two filters with slightly different frequency range and they will shortcut each other. But we can use that as an advantage.
If both these filters have low real and low imaginary impedance in each others pass band is it possible to get a quite good 50 Ohm match and with low loss by a impedance matching network over whole frequency range covered by two SAW filters.
From each SAW, connect it to a network resulting in 45 degree delay at 50 Ohm. Each network can be done with just a inductor and a cap.
Connect these both network with each other, they will be almost blind for each other due to the total of delay is 90 degree.
A additional network is connected to same spot as the both other networks are interconnected, for impedance correction to a single 50 Ohm output.
A alternative method is to use coaxial cables instead of L/C network.
Two SAW's with overlapping bands, phasing part can maybe be solved for a part of the frequency range they have in common.
Worse is that one SAW have a step impedance/phase variation in the middle of pass band for the other SAW.
Cheapest way to reduce that effect is as biff44 says, two 3 dB resistor network. You will still get a very nonlinear frequency and impedance response, but variations will be limited so response not becomes absolute zero in parts of the total pass band.
About the resistor network design, think about it as a 3-way power divider.