Good morning Johan,
What you're trying to do should work fine. EAPS ring Yellow can also use the existing shared-link Blue and Green are using.
As far as I am aware, the number of EAPS rings currently supported across a single common link is equivalent to the number of EAPS rings currently supported on the platform+license you're using. So. If you have the Advanced Edge license on say, X460-G2, then you're looking at 64 EAPS domains. You find details around limitations in the firmware release notes and feature license requirements.
Hope this answers your question