You can, but not both via the native sync. As Josh suggests, I would integrate SAP via the API and Salesforce via the native sync. This is an advanced configuration, so I would recommend working with an experienced system integrator.
Thanks Jep and Josh. I think we'll have a look at connecting through the API. It's some simple lookups we need to perform, so nothing fancy. We're having a meeting with the system integrators tomorrow, and just wanted to check prior to this.