Utilization of cenvat of one unit by another unit

Yes it is possible, you have to get registered with Large Taxpayer Unit (LTU) and then you can simply transfer the credit available from one unit to another by a transfer voucher and also can utilise the sameas per the Cenvat Credit Rules.

Other than LTU - The reason for the accumulation maybe examined. It could be due to value addition being done in one unit more and job work usage and possibly supply to EOU or export. If export then rebate/ procurement without paymentof duty can be examined. If local only then possibility of sharing input service credits thru input service distributor can be see.

Procurement and receipt planning can see that credit available in unit which has deficiency. 

In 2015 there is one amendment for LTU and after that amendment LTU also can't transfer the credit. 

The unit can plan to reduce the input or it can go for refund depending on eligibility.