A first thought about a multi-universe Cosmos

Hindu cosmologists have postulated the possibility of many, many universes co-existing with the one we inhabit.

Would that mean that our universe does not occupy infinite space? That is, that it does not stretch out in all directions for ever and ever? If it does not, could it be limited, circumscribed, by some sort of envelope?

If so, when modern scientists explain the movement of galaxies away from one another (as observed by the Hubble Telescope) by referring to the space containing the galaxies as expanding, is it this envelope which is expanding outwards, stretching like a balloon being blown up?

When modern cosmologists talk about a multiverse Cosmos, that is a multi-universe Cosmos, are they not referring to a gathering of universes, each contained or constrained by its own balloon-like envelope? Does this make credible the concept of ‘worm-holes’ linking one universe with another?