LMK04828: Isolation of Inter and Intra-Clock Groups

We are using LMK04828B device on our board. We generate one output clock (2400 MHz) for ADC and one for FPGA (600 MHz). However we have observed that these two clocks couple with each other which resulted in spurs and harmonics in the ADC spectrum. We realized that these two output clocks are in the same Clock Group of LMK device. What is the isolation between two clocks of the same clock group and different groups? Is there any option to increase isolation performance of LMK device. Should we use clocks from different Clock Groups which requires revision of our PCB design.