Χρησιμοποιείται μεταφορικά στη συγκεκριμένη πρόταση.
Ασημίνα, ένας εύκολος τρόπος για να βρεις τη μετάφραση είναι ο εξής:

Ανοίγεις ΕΛΛΗΝΙΚΟ ΛΕΞΙΚΟ, βρίσκεις τη λέξη που ψάχνεις, διαβάζεις τις διάφορες ερμηνείες της και ψάχνει ένα σχετικό συνώνυμο.

Ελπίζω να βοήθησα.

(μπορείς όντως να βάλεις και osmosis αν και θεωρώ το amalgamation καλύτερο)
...it is important that an amalgamation be created by all the participants of the thoughts, goals and frameworks in which the positions and speeches could be centered (ή contained).

First things first: I would refrain from using the noun (assimilation) and opt for the verb in your sentence.
Now, if you take a look at the definitions of "osmosis", you will not only come across the purely biological term, but metaphorical ones as well. Although I partly agree with Evdoxia (long time no see - φιλάκια) on "interaction", I get the feeling this is not the one you're looking for (i.e. an interaction or interchange, as of cultural groups or traits by mutual penetration).
I prefer this one: a usu. effortless, often unconscious absorption or assimilation (as of ideas or influences) by a seemingly general permeation (e.g. absorbing democratic habits and ideals as by ~), more however in the sense of receiving into the mind, considering and thoroughly comprehending.
Now, in your example I would go for:
"It is crucial/important that the participants assimilate the concept, objectives and framework, etc."
Just a thought.
Efi