use EnVisage

alter table Resource add TeamId uniqueidentifier null
go

ALTER TABLE [dbo].[Resource]  WITH CHECK ADD  CONSTRAINT [FK_Resource_Team] FOREIGN KEY([TeamId])
REFERENCES [dbo].[Team] ([Id])
GO

ALTER TABLE [dbo].[Resource] CHECK CONSTRAINT [FK_Resource_Team]
GO

update Resource 
set TeamId = (select top 1 a.TeamId
from (select *, ROW_NUMBER() OVER (PARTITION BY TeamId ORDER BY ResourceId) AS RowNumber from Resource2Teams) as a
where a.ResourceId = Id and a.RowNumber = 1)

drop table Resource2Teams