Floating multiple sealed lead acid batteries in parallel
In theory it is OK to connect them in parallel with two conditions:

Each battery must be in a state where it can be voltage charged.  This is fine for lead acid batteries unless they are very run down.  Very discharged lead-acid batteries have to be charged with fixed current until they get to a minimum voltage, then they can be voltage charged.

The power supply is capable of maintaining the fixed float voltage.



In practise, I think it's a good idea to put at least a diode in series with each battery just because stuff happens.  Of course the power supply voltage needs to be adjusted to get the float charge voltage after the diodes.