How to pay partial payroll liabilities?

Hello,

When I run payroll we deduct medical insurance from our employee's paychecks and that accrues onto a liability account. However, that amount is not enough to pay the entire insurance bill. How do I go about paying our insurance company with one check? If I go to pay payroll liabilities, it only allows me to make a check for the amount withheld, I need to add the company portion to that check.

I don't want to send two checks, how can I avoid that?

Thanks,

Ron