Ephesians 4:4ff says,
There is one body and one Spirit, just as you were called in one hope of your calling; one Lord, one faith, one baptism;
So we may reason: One body –> one baptism
1 Corinthians 10:1-4 says,
Moreover, brethren, I do not want you to be unaware that all our fathers were under the cloud, all passed through the sea, all were baptized into Moses in the cloud and in the sea, all ate the same spiritual food, and all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ.
So we may reason: One body –> one baptism –> One cup
The real question is, who is excluded from the “all?”