The phrase "a joint problem" is correct and usable in written English.
It can be used to describe an issue or challenge that is shared or experienced by multiple parties or individuals.
Example: "The environmental crisis is a joint problem that requires collaboration from governments, businesses, and citizens alike."
Alternatives: "a shared issue" or "a collective challenge".
Maybe even frame the issue as a joint problem on which you two can work together.
The former seems more of a distributive problem, the latter a joint problem to be solved.
To surmount the problem of obtaining local solutions, we have investigated the utility of using a joint problem formulation.
When dealing with conflict in the workplace, capitalizing on differences can help employees transition from disputants to negotiators focused on solving a joint problem to their mutual benefit.
It has strengthened the relationship between residents and agencies through case findings and a joint problem solving approach, reduced the impact of crime and victimisation in the area, improved housing and brought about regeneration of the area.
Co-construction, from a situated cognition perspective, refers to the fragile process of having two or more individuals collaboratively construct and maintain a shared understanding, or a joint problem space by constant negotiations and recreations of meaning.
The goal is to move from the appallingly common "win-lose" pattern to a joint problem-solving activity.
Approach the interim role as a joint problem-solving exercise, one involving you, your boss, and others in the organization.
When you ask someone for advice rather than issuing demands or attacks, you frame your negotiation as a joint problem-solving task and establish a norm of collaboration.
Mr. Shapiro, speaking from his home in Arlington, Mass., agreed that establishing a rapport was crucial to successful bargaining, and said he often asks a salesclerk for advice: a tactic that transforms the encounter from "an adversarial game" into a joint problem-solving session.
When pitching to customers, effective sales reps adopt a joint problem-solving approach.
