Make Reservation from Osaka to Sapporo

Hi,
We’re planning to travel from Shin Osaka to Sapporo.
1. From Shin Osaka to Tokyo, we tame Shinkansen Hikari 504.
2. From Tokyo to Shin-Hokodate-Hokuto, we take shinkansen Hayabusa 11.
3. From Shin-Hokodate-Hokuto, we take Ltd Exp Super Hokuto 13.

Can I make resevation for those train above in single reservation in Osaka, or should I make reservation in Osaka for Hikari 504, in Tokyo for Hayabusa 11 and in Hokuto for Super Hokuto 13?

Thanks