Cornelia

May need some additional context before I can answer you properly - but lets start things off...

We need to step back a bit - what exactly is the issue you are trying to address?   Are there situation where 'problems' happen and teams dont engage/disengage properly, or prioritize activity as they should?   Or, is there a problem team that works to a pace that doesn't fit that required to respond to a situation?

Generally, I recommend SLAs are built at the request response level - service request, and incidents are recorded as a type of request.   They govern a specific situation, or as specific as can be defined.

As a rule, escalation, and thereby the concept of an OLA, work at the same level - governing the pace of a response to a service request.

Problem management and problems, are not subject to escalation, this is because they are investigations of the unknown when they start.  

Yes, problem management may be required to authorize a workaround in flight, but again, no escalation is in play for them because they mission is the antithesis of problems.   (fix it quick versus fix it permanently).

That said, there is no reason why an OLA could not be crafted for a problem management function - to perhaps put governance boundaries around how they are involved in incident management, and conduct problem management activities at large.

Is this helping?   I need your guidance and further context as to the issue before going much further...