Separating slots in Bigquery by process

[Cayo_dias]

I separate the slots for the use case mentioned in this question (https://www.googlecloudcommunity.com/gc/Data-Analytics/How-to-point-a-jobs-in-Bigquery-to-a-especifi...), the project 1 will have slots for ETL process and project 2 for metabase usage. 

Can I create a reservation in Project 1 and attribute Project 2 for it? Or will it be necessary to create this new reservation in Project 2?