DPST relay from SPST?

I have a problem: I need to use a DC solid state DPST relay (I can't use electromechanical relays) and I can't find one that meets my spec (100VDC, 15A). So I want to make one from 2 SPST relays. The problem is that if I use this design:

INA - SPST ---------------------------> OUT
^
|
|
INB - SPST ----------------------

There's a chance of my inputs being shorted to each other due to delay. Which is not acceptable. Does anyone have a idea how I can ensure that doesn't happen? In the simplest way without resorting to too much components?

Please explain your problem .... requirements ... a little more.
What are you trying to accomplish?
Can you use two single solid state relays, with the control voltages activated by a flip-flop?

Connect the LED inputs of the two SPST SSRs in series.
+V...resistor...+Input-...+Input-...GND (If the SSRs have internal current limiting resistors drop my resistor)
This makes a DPST SSR.

Ken