Can you use rectifiers from different transformer sources in parallel?
What you show will work in that no harm is done and you will get a DC voltage out.  This might be a reasonable design if one or the other tranformer might not be powered sometimes, and you want the system to work when either is powered.

However, if you are expecting twice the current output, then it might not work so well.  Two transformers, even of the same model, will have a little different output voltage.  One of them will take more of the load.  The impedance of each transformer will help balance the load, but you can't count on 50% for each.  How much you can count on load sharing has to do with the transformer impedances and the expected part to part variation.  If the transformers are different models, then you should size everything so that each one can supply the full current by itself.