Using one counter (Dev1/ctr0), how to prevent activation (High state output at Dev1/PFI13) of another counter (Dev1/ctr1)?

Hi, i'm using the PCI-6255 and PCI-6251, both have 2 counters. I have the problem that when i use just one counter, the other generate a high output in the PFI line during the time when the first counter is active. It is possible to avoid this situation? I show the issue in the time diagram.

Thanks