Praise be to Allah.
There is nothing wrong with contacting fellow workers via text messages, so long as it is limited to work matters and organization.
With regard to personal messages between the genders, the basic principle is that it is not allowed, because of the negative consequences to which it may lead, such as infatuation and what that leads to. But if the message is sent to all workers, then there is nothing wrong with it in that case, because the negative consequences are no longer a concern.
And Allah knows best.