So what you are saying is that you have an entity and that you currently have 100% of the equity (ownership). The plan is to grant partial ownership in your venture to these two other companies?
What would be more typical in the corporate world would be to create a new corporation with stock in the new corporation owned by your three companies. This would be a "joint venture" and would operate separately from each of the existing companies.
By giving ownership in your venture to their companies you are entering into a one-sided deal in that their companies can continue to operate autonomously while control in your venture is being diluted and they have access to all your dealings.