Transformer Synchonization

Sounds like you want to parallel these transformers. In addition to Tornado's query on vector group, are the transformers otherwise identical; same ratings, impedances, tap changer settings. etc. If so then it should be "easy", but you also have to ensure that your surrounding switchgear can handle the quadrupled short circuit forces.

Check that both transformers are identical in all electrical aspects and powered by the same source at the primary side. Ensure that the secondary side busbar, cables, switchgear etc are rated to withstand cumulative fualt MVA by both transformers, yes you can parallel both.

But keep it mind to parallel and operate both transformers at the same tap position. This is to avoid reactive circulation current and unneccassary heat developed.

parallel operation of transformers are normal in many utilities, but before that do proper fault calculations and short circuit withstand capacity study for all secondary equipments.

Note : - if both transformers are powered by different sources then dont parallel it. First consult a experienced protection engineer.

Good luck.