This is possible, but it requires compliance with the policy on Conflicts of Interest.
Indeed, in the present case, a relationship of interest exists and it could lead to a potential conflict of interest with regard to the positions held by the two persons:
If they do not directly or indirectly interfere in the relationship between the two companies, then there is no problem.
Otherwise, this is not possible.
In any case, what is important is transparency: you must communicate this type of situation to your line management to ensure that there is no problem or that it can be reported to your Legal and Compliance Director to obtain the requisite approvals.