I went to Bayern vs Freiburg in December and what I did was get on the Bayern site, I think you have to create an account, and then get on the ticket exchange and just keep hitting refresh.
I had a tab open at work and I'd hit refresh every so often (for weeks, but I was being picky) and then some tickets were finally posted. It looks like the exchange isn't open for that game yet.
There are also hotel packages and stuff you could try looking at.
For five tickets though that might be difficult. It took me a while to find two decent seats together so y'all might consider splitting up. But that's what we did.
Hardest ticket acquisition of my entire life, but I stayed committed to refreshing the market site and eventually hit. Worth it though! Good luck!