Yes.  The procedure depends on whether they are using all or part of the money from the check:

• If just using part of the funds, after entering the outside check amount, you would enter a deposit amount for everything except the amount of the tickets, then enter Proc code R, then use F5-Post .  The Miscellaneous Receipts screen will appear.  (As an alternative, instead of using Proc Code R and F5, simply use F8-M/R to post and proceed to the Misc. Receipts screen.)
• If using the entire check to pay for the M/R, after entering in the outside check you would simply press F8-M/R to proceed to the M/R screen, using the cash back amount to pay for the tickets.