The secondary union is a legal person separate from main trade union.

It can independently manage, maintain and improve one or more buildings.

The secondary trade union may be provided for by co-ownership rules or be decided in the assembly by a vote of the absolute majority co-owners.

There can be as many secondary unions as there are buildings.

Co-owners of different buildings may decide among themselves to set up a secondary trade union.

The secondary trade union must be managed by a condominium trustee.

That trustee may be the same as the trustee of the main union.

He can have a trade union council whereas the main union decided not to have one, or vice versa.

The secondary union has its own heritage.

So he has his own accounting.

He votes his provisional budget.

Yes, the secondary union can take legal action to ensure, for example, compliance with the co-ownership rules in its provisions concerning only the co-owners of its vessel(s).