Would a JR pass be cheaper?

Hi there,

Yes you will be able to make good savings with the JR Pass.

Just by doing the following travel,
Osaka - Hiroshima ¥ 10,440
Hiroshima - Osaka ¥ 10,440
Osaka - Tokyo ¥ 14,650

For a total of ¥ 35,530 or ¥ 6,420 in savings as the 7 day JR Pass is ¥ 29,110. You can also use to pass for local travel in Osaka, Tokyo, to Kyoto, to Disneyland and the airport. Adding even more to your savings.

Hope this helps!
Daniel